NAME
systemd.network - Network configurationSYNOPSIS
network.networkDESCRIPTION
A plain ini-style text file that encodes network configuration for matching network interfaces, used by systemd-networkd(8). See systemd.syntax(7) for a general description of the syntax. The main network file must have the extension .network; other extensions are ignored. Networks are applied to links whenever the links appear. The .network files are read from the files located in the system network directories /lib/systemd/network and /usr/local/lib/systemd/network, the volatile runtime network directory /run/systemd/network and the local administration network directory /etc/systemd/network. All configuration files are collectively sorted and processed in alphanumeric order, regardless of the directories in which they live. However, files with identical filenames replace each other. It is recommended that each filename is prefixed with a number (e.g. 10-eth0.network). Otherwise, the default .network files or those generated by systemd-network-generator.service(8) may take precedence over user configured files. Files in /etc/ have the highest priority, files in /run/ take precedence over files with the same name under /usr/. This can be used to override a system-supplied configuration file with a local file if needed. As a special case, an empty file (file size 0) or symlink with the same name pointing to /dev/null disables the configuration file entirely (it is "masked"). Along with the network file foo.network, a "drop-in" directory foo.network.d/ may exist. All files with the suffix ".conf" from this directory will be merged in the alphanumeric order and parsed after the main file itself has been parsed. This is useful to alter or add configuration settings, without having to modify the main configuration file. Each drop-in file must have appropriate section headers. In addition to /etc/systemd/network, drop-in ".d" directories can be placed in /lib/systemd/network or /run/systemd/network directories. Drop-in files in /etc/ take precedence over those in /run/ which in turn take precedence over those in /lib/. Drop-in files under any of these directories take precedence over the main network file wherever located.[MATCH] SECTION OPTIONS
The network file contains a [Match] section, which determines if a given network file may be applied to a given interface; and a [Network] section specifying how the interface should be configured. The first (in alphanumeric order) of the network files that matches a given interface is applied, all later files are ignored, even if they match as well. A network file is said to match a network interface if all matches specified by the [Match] section are satisfied. When a network file does not contain valid settings in [Match] section, then the file will match all interfaces and systemd-networkd warns about that. Hint: to avoid the warning and to make it clear that all interfaces shall be matched, add the following:Name=*
A whitespace-separated list of hardware
addresses. The acceptable formats are:
colon-delimited hexadecimal
The total length of each MAC address must be 4 (for IPv4 tunnel), 6 (for
Ethernet), 16 (for IPv6 tunnel), or 20 (for InfiniBand). This option may
appear more than once, in which case the lists are merged. If the empty string
is assigned to this option, the list of hardware addresses defined prior to
this is reset. Defaults to unset.
PermanentMACAddress=
Each field must be one byte. E.g.
"12:34:56:78:90:ab" or "AA:BB:CC:DD:EE:FF".
hyphen-delimited hexadecimal
Each field must be one byte. E.g.
"12-34-56-78-90-ab" or "AA-BB-CC-DD-EE-FF".
dot-delimited hexadecimal
Each field must be two bytes. E.g.
"1234.5678.90ab" or "AABB.CCDD.EEFF".
IPv4 address format
E.g. "127.0.0.1" or
"192.168.0.1".
IPv6 address format
E.g.
"2001:0db8:85a3::8a2e:0370:7334" or "::1".
A whitespace-separated list of hardware's
permanent addresses. While MACAddress= matches the device's current MAC
address, this matches the device's permanent MAC address, which may be
different from the current one. Use full colon-, hyphen- or dot-delimited
hexadecimal, or IPv4 or IPv6 address format. This option may appear more than
once, in which case the lists are merged. If the empty string is assigned to
this option, the list of hardware addresses defined prior to this is reset.
Defaults to unset.
Path=
A whitespace-separated list of shell-style
globs matching the persistent path, as exposed by the udev property
ID_PATH.
Driver=
A whitespace-separated list of shell-style
globs matching the driver currently bound to the device, as exposed by the
udev property ID_NET_DRIVER of its parent device, or if that is not
set, the driver as exposed by ethtool -i of the device itself. If the
list is prefixed with a "!", the test is inverted.
Type=
A whitespace-separated list of shell-style
globs matching the device type, as exposed by networkctl list. If the
list is prefixed with a "!", the test is inverted. Some valid values
are "ether", "loopback", "wlan",
"wwan". Valid types are named either from the udev
"DEVTYPE" attribute, or "ARPHRD_" macros in
linux/if_arp.h, so this is not comprehensive.
Kind=
A whitespace-separated list of shell-style
globs matching the device kind, as exposed by networkctl status
INTERFACE or ip -d link show INTERFACE.
If the list is prefixed with a "!", the test is inverted. Some valid
values are "bond", "bridge", "gre",
"tun", "veth". Valid kinds are given by netlink's
"IFLA_INFO_KIND" attribute, so this is not comprehensive.
Property=
A whitespace-separated list of udev property
names with their values after equals sign ("="). If multiple
properties are specified, the test results are ANDed. If the list is prefixed
with a "!", the test is inverted. If a value contains white spaces,
then please quote whole key and value pair. If a value contains quotation,
then please escape the quotation with "\".
Example: if a .link file has the following:
then, the .link file matches only when an interface has all the above three
properties.
Name=
Property=ID_MODEL_ID=9999 "ID_VENDOR_FROM_DATABASE=vendor name" "KEY=with \"quotation\""
A whitespace-separated list of shell-style
globs matching the device name, as exposed by the udev property
"INTERFACE", or device's alternative names. If the list is prefixed
with a "!", the test is inverted.
WLANInterfaceType=
A whitespace-separated list of wireless
network type. Supported values are "ad-hoc", "station",
"ap", "ap-vlan", "wds", "monitor",
"mesh-point", "p2p-client", "p2p-go",
"p2p-device", "ocb", and "nan". If the list is
prefixed with a "!", the test is inverted.
SSID=
A whitespace-separated list of shell-style
globs matching the SSID of the currently connected wireless LAN. If the list
is prefixed with a "!", the test is inverted.
BSSID=
A whitespace-separated list of hardware
address of the currently connected wireless LAN. Use full colon-, hyphen- or
dot-delimited hexadecimal. See the example in MACAddress=. This option
may appear more than once, in which case the lists are merged. If the empty
string is assigned to this option, the list is reset.
Host=
Matches against the hostname or machine ID of
the host. See ConditionHost= in systemd.unit(5) for details.
When prefixed with an exclamation mark ("!"), the result is negated.
If an empty string is assigned, the previously assigned value is
cleared.
Virtualization=
Checks whether the system is executed in a
virtualized environment and optionally test whether it is a specific
implementation. See ConditionVirtualization= in systemd.unit(5)
for details. When prefixed with an exclamation mark ("!"), the
result is negated. If an empty string is assigned, the previously assigned
value is cleared.
KernelCommandLine=
Checks whether a specific kernel command line
option is set. See ConditionKernelCommandLine= in
systemd.unit(5) for details. When prefixed with an exclamation mark
("!"), the result is negated. If an empty string is assigned, the
previously assigned value is cleared.
KernelVersion=
Checks whether the kernel version (as reported
by uname -r) matches a certain expression. See
ConditionKernelVersion= in systemd.unit(5) for details. When
prefixed with an exclamation mark ("!"), the result is negated. If
an empty string is assigned, the previously assigned value is cleared.
Credential=
Checks whether the specified credential was
passed to the systemd-networkd.service service. See System and Service
Credentials[1] for details. When prefixed with an exclamation mark
("!"), the result is negated. If an empty string is assigned, the
previously assigned value is cleared.
Architecture=
Checks whether the system is running on a
specific architecture. See ConditionArchitecture= in
systemd.unit(5) for details. When prefixed with an exclamation mark
("!"), the result is negated. If an empty string is assigned, the
previously assigned value is cleared.
Firmware=
Checks whether the system is running on a
machine with the specified firmware. See ConditionFirmware= in
systemd.unit(5) for details. When prefixed with an exclamation mark
("!"), the result is negated. If an empty string is assigned, the
previously assigned value is cleared.
[LINK] SECTION OPTIONS
The [Link] section accepts the following keys: MACAddress=The hardware address to set for the
device.
MTUBytes=
The maximum transmission unit in bytes to set
for the device. The usual suffixes K, M, G, are supported and are understood
to the base of 1024.
Note that if IPv6 is enabled on the interface, and the MTU is chosen below 1280
(the minimum MTU for IPv6) it will automatically be increased to this
value.
ARP=
Takes a boolean. If set to true, the ARP
(low-level Address Resolution Protocol) for this interface is enabled. When
unset, the kernel's default will be used.
For example, disabling ARP is useful when creating multiple MACVLAN or VLAN
virtual interfaces atop a single lower-level physical interface, which will
then only serve as a link/"bridge" device aggregating traffic to the
same physical link and not participate in the network otherwise. Defaults to
unset.
Multicast=
Takes a boolean. If set to true, the multicast
flag on the device is enabled. Defaults to unset.
AllMulticast=
Takes a boolean. If set to true, the driver
retrieves all multicast packets from the network. This happens when multicast
routing is enabled. Defaults to unset.
Promiscuous=
Takes a boolean. If set to true, promiscuous
mode of the interface is enabled. Defaults to unset.
If this is set to false for the underlying link of a "passthru" mode
MACVLAN/MACVTAP, the virtual interface will be created with the
"nopromisc" flag set.
Unmanaged=
Takes a boolean. When "yes", no
attempts are made to bring up or configure matching links, equivalent to when
there are no matching network files. Defaults to "no".
This is useful for preventing later matching network files from interfering with
certain interfaces that are fully controlled by other applications.
Group=
Link groups are similar to port ranges found
in managed switches. When network interfaces are added to a numbered group,
operations on all the interfaces from that group can be performed at once.
Takes an unsigned integer in the range 0...2147483647. Defaults to
unset.
RequiredForOnline=
Takes a boolean or a minimum operational state
and an optional maximum operational state. Please see networkctl(1) for
possible operational states. When "yes", the network is deemed
required when determining whether the system is online (including when running
systemd-networkd-wait-online). When "no", the network is
ignored when determining the online state. When a minimum operational state
and an optional maximum operational state are set, "yes" is implied,
and this controls the minimum and maximum operational state required for the
network interface to be considered online.
Defaults to "yes" when ActivationPolicy= is not set, or set to
"up", "always-up", or "bound". Defaults to
"no" when ActivationPolicy= is set to "manual" or
"down". This is forced to "no" when
ActivationPolicy= is set to "always-down".
The network will be brought up normally (as configured by
ActivationPolicy=), but in the event that there is no address being
assigned by DHCP or the cable is not plugged in, the link will simply remain
offline and be skipped automatically by systemd-networkd-wait-online if
"RequiredForOnline=no".
RequiredFamilyForOnline=
Takes an address family. When specified, an IP
address in the given family is deemed required when determining whether the
link is online (including when running systemd-networkd-wait-online).
Takes one of "ipv4", "ipv6", "both", or
"any". Defaults to "any". Note that this option has no
effect if "RequiredForOnline=no", or if
"RequiredForOnline=" specifies a minimum operational state below
"degraded".
ActivationPolicy=
Specifies the policy for
systemd-networkd managing the link administrative state. Specifically,
this controls how systemd-networkd changes the network device's
"IFF_UP" flag, which is sometimes controlled by system
administrators by running e.g., ip link set dev eth0 up or ip link
set dev eth0 down, and can also be changed with networkctl up eth0
or networkctl down eth0.
Takes one of "up", "always-up", "manual",
"always-down", "down", or "bound". When
"manual", systemd-networkd will not change the link's admin
state automatically; the system administrator must bring the interface up or
down manually, as desired. When "up" (the default) or
"always-up", or "down" or "always-down",
systemd-networkd will set the link up or down, respectively, when the
interface is (re)configured. When "always-up" or
"always-down", systemd-networkd will set the link up or down,
respectively, any time systemd-networkd detects a change in the
administrative state. When BindCarrier= is also set, this is
automatically set to "bound" and any other value is ignored.
When the policy is set to "down" or "manual", the default
value of RequiredForOnline= is "no". When the policy is set
to "always-down", the value of RequiredForOnline= forced to
"no".
The administrative state is not the same as the carrier state, so using
"always-up" does not mean the link will never lose carrier. The link
carrier depends on both the administrative state as well as the network
device's physical connection. However, to avoid reconfiguration failures, when
using "always-up", IgnoreCarrierLoss= is forced to
true.
[SR-IOV] SECTION OPTIONS
The [SR-IOV] section accepts the following keys. Specify several [SR-IOV] sections to configure several SR-IOVs. SR-IOV provides the ability to partition a single physical PCI resource into virtual PCI functions which can then be injected into a VM. In the case of network VFs, SR-IOV improves north-south network performance (that is, traffic with endpoints outside the host machine) by allowing traffic to bypass the host machine’s network stack. VirtualFunction=Specifies a Virtual Function (VF), lightweight
PCIe function designed solely to move data in and out. Takes an integer in the
range 0...2147483646. This option is compulsory.
VLANId=
Specifies VLAN ID of the virtual function.
Takes an integer in the range 1...4095.
QualityOfService=
Specifies quality of service of the virtual
function. Takes an integer in the range 1...4294967294.
VLANProtocol=
Specifies VLAN protocol of the virtual
function. Takes "802.1Q" or "802.1ad".
MACSpoofCheck=
Takes a boolean. Controls the MAC spoof
checking. When unset, the kernel's default will be used.
QueryReceiveSideScaling=
Takes a boolean. Toggle the ability of
querying the receive side scaling (RSS) configuration of the virtual function
(VF). The VF RSS information like RSS hash key may be considered sensitive on
some devices where this information is shared between VF and the physical
function (PF). When unset, the kernel's default will be used.
Trust=
Takes a boolean. Allows one to set trust mode
of the virtual function (VF). When set, VF users can set a specific feature
which may impact security and/or performance. When unset, the kernel's default
will be used.
LinkState=
Allows one to set the link state of the
virtual function (VF). Takes a boolean or a special value "auto".
Setting to "auto" means a reflection of the physical function (PF)
link state, "yes" lets the VF to communicate with other VFs on this
host even if the PF link state is down, "no" causes the hardware to
drop any packets sent by the VF. When unset, the kernel's default will be
used.
MACAddress=
Specifies the MAC address for the virtual
function.
[NETWORK] SECTION OPTIONS
The [Network] section accepts the following keys: Description=A description of the device. This is only used
for presentation purposes.
DHCP=
Enables DHCPv4 and/or DHCPv6 client support.
Accepts "yes", "no", "ipv4", or
"ipv6". Defaults to "no".
Note that DHCPv6 will by default be triggered by Router Advertisements, if
reception is enabled, regardless of this parameter. By explicitly enabling
DHCPv6 support here, the DHCPv6 client will be started in the mode specified
by the WithoutRA= setting in the [DHCPv6] section, regardless of the
presence of routers on the link, or what flags the routers pass. See
IPv6AcceptRA=.
Furthermore, note that by default the domain name specified through DHCP is not
used for name resolution. See option UseDomains= below.
See the [DHCPv4] or [DHCPv6] sections below for further configuration options
for the DHCP client support.
DHCPServer=
Takes a boolean. If set to "yes",
DHCPv4 server will be started. Defaults to "no". Further settings
for the DHCP server may be set in the [DHCPServer] section described
below.
LinkLocalAddressing=
Enables link-local address autoconfiguration.
Accepts a boolean, ipv4, and ipv6. An IPv6 link-local address is
configured when yes or ipv6. An IPv4 link-local address is
configured when yes or ipv4 and when DHCPv4 autoconfiguration
has been unsuccessful for some time. (IPv4 link-local address
autoconfiguration will usually happen in parallel with repeated attempts to
acquire a DHCPv4 lease).
Defaults to no when KeepMaster= or Bridge= is set or when
the specified MACVLAN=/MACVTAP= has Mode=passthru, or
ipv6 otherwise.
IPv6LinkLocalAddressGenerationMode=
Specifies how IPv6 link-local address is
generated. Takes one of "eui64", "none",
"stable-privacy" and "random". When unset,
"stable-privacy" is used if IPv6StableSecretAddress= is
specified, and if not, "eui64" is used. Note that if
LinkLocalAddressing= is "no" or "ipv4", then
IPv6LinkLocalAddressGenerationMode= will be ignored. Also, even if
LinkLocalAddressing= is "yes" or "ipv6", setting
IPv6LinkLocalAddressGenerationMode=none disables to configure an IPv6
link-local address.
IPv6StableSecretAddress=
Takes an IPv6 address. The specified address
will be used as a stable secret for generating IPv6 link-local address. If
this setting is specified, and IPv6LinkLocalAddressGenerationMode= is
unset, then IPv6LinkLocalAddressGenerationMode=stable-privacy is
implied. If this setting is not specified, and "stable-privacy" is
set to IPv6LinkLocalAddressGenerationMode=, then a stable secret
address will be generated from the local machine ID and the interface
name.
IPv4LLStartAddress=
Specifies the first IPv4 link-local address to
try. Takes an IPv4 address for example 169.254.1.2, from the link-local
address range: 169.254.0.0/16 except for 169.254.0.0/24 and 169.254.255.0/24.
This setting may be useful if the device should always have the same address
as long as there is no address conflict. When unset, a random address will be
automatically selected. Defaults to unset.
IPv4LLRoute=
Takes a boolean. If set to true, sets up the
route needed for non-IPv4LL hosts to communicate with IPv4LL-only hosts.
Defaults to false.
DefaultRouteOnDevice=
Takes a boolean. If set to true, sets up the
IPv4 default route bound to the interface. Defaults to false. This is useful
when creating routes on point-to-point interfaces. This is equivalent to e.g.
the following,
or,
Currently, there are no way to specify e.g., the table for the route configured
by this setting. To configure the default route with such an additional
property, please use the following instead:
If you'd like to create an IPv6 default route bound to the interface, please use
the following:
LLMNR=
ip route add default dev veth99
[Route] Gateway=0.0.0.0
[Route] Gateway=0.0.0.0 Table=1234
[Route] Gateway=:: Table=1234
Takes a boolean or "resolve". When
true, enables Link-Local Multicast Name Resolution[2] on the link. When
set to "resolve", only resolution is enabled, but not host
registration and announcement. Defaults to true. This setting is read by
systemd-resolved.service(8).
MulticastDNS=
Takes a boolean or "resolve". When
true, enables Multicast DNS[3] support on the link. When set to
"resolve", only resolution is enabled, but not host or service
registration and announcement. Defaults to false. This setting is read by
systemd-resolved.service(8).
DNSOverTLS=
Takes a boolean or "opportunistic".
When true, enables DNS-over-TLS[4] support on the link. When set to
"opportunistic", compatibility with non-DNS-over-TLS servers is
increased, by automatically turning off DNS-over-TLS servers in this case.
This option defines a per-interface setting for resolved.conf(5)'s
global DNSOverTLS= option. Defaults to unset, and the global setting
will be used. This setting is read by
systemd-resolved.service(8).
DNSSEC=
Takes a boolean or
"allow-downgrade". When true, enables DNSSEC[5] DNS
validation support on the link. When set to "allow-downgrade",
compatibility with non-DNSSEC capable networks is increased, by automatically
turning off DNSSEC in this case. This option defines a per-interface setting
for resolved.conf(5)'s global DNSSEC= option. Defaults to unset,
and the global setting will be used. This setting is read by
systemd-resolved.service(8).
DNSSECNegativeTrustAnchors=
A space-separated list of DNSSEC negative
trust anchor domains. If specified and DNSSEC is enabled, look-ups done via
the interface's DNS server will be subject to the list of negative trust
anchors, and not require authentication for the specified domains, or anything
below it. Use this to disable DNSSEC authentication for specific private
domains, that cannot be proven valid using the Internet DNS hierarchy.
Defaults to the empty list. This setting is read by
systemd-resolved.service(8).
LLDP=
Controls support for Ethernet LLDP packet
reception. LLDP is a link-layer protocol commonly implemented on professional
routers and bridges which announces which physical port a system is connected
to, as well as other related data. Accepts a boolean or the special value
"routers-only". When true, incoming LLDP packets are accepted and a
database of all LLDP neighbors maintained. If "routers-only" is set
only LLDP data of various types of routers is collected and LLDP data about
other types of devices ignored (such as stations, telephones and others). If
false, LLDP reception is disabled. Defaults to "routers-only". Use
networkctl(1) to query the collected neighbor data. LLDP is only
available on Ethernet links. See EmitLLDP= below for enabling LLDP
packet emission from the local system.
EmitLLDP=
Controls support for Ethernet LLDP packet
emission. Accepts a boolean parameter or the special values
"nearest-bridge", "non-tpmr-bridge" and
"customer-bridge". Defaults to false, which turns off LLDP packet
emission. If not false, a short LLDP packet with information about the local
system is sent out in regular intervals on the link. The LLDP packet will
contain information about the local hostname, the local machine ID (as stored
in machine-id(5)) and the local interface name, as well as the pretty
hostname of the system (as set in machine-info(5)). LLDP emission is
only available on Ethernet links. Note that this setting passes data suitable
for identification of host to the network and should thus not be enabled on
untrusted networks, where such identification data should not be made
available. Use this option to permit other systems to identify on which
interfaces they are connected to this system. The three special values control
propagation of the LLDP packets. The "nearest-bridge" setting
permits propagation only to the nearest connected bridge,
"non-tpmr-bridge" permits propagation across Two-Port MAC Relays,
but not any other bridges, and "customer-bridge" permits propagation
until a customer bridge is reached. For details about these concepts, see
IEEE 802.1AB-2016[6]. Note that configuring this setting to true is
equivalent to "nearest-bridge", the recommended and most restricted
level of propagation. See LLDP= above for an option to enable LLDP
reception.
BindCarrier=
A link name or a list of link names. When set,
controls the behavior of the current link. When all links in the list are in
an operational down state, the current link is brought down. When at least one
link has carrier, the current interface is brought up.
This forces ActivationPolicy= to be set to "bound".
Address=
A static IPv4 or IPv6 address and its prefix
length, separated by a "/" character. Specify this key more than
once to configure several addresses. The format of the address must be as
described in inet_pton(3). This is a short-hand for an [Address]
section only containing an Address key (see below). This option may be
specified more than once.
If the specified address is "0.0.0.0" (for IPv4) or "::"
(for IPv6), a new address range of the requested size is automatically
allocated from a system-wide pool of unused ranges. Note that the prefix
length must be equal or larger than 8 for IPv4, and 64 for IPv6. The allocated
range is checked against all current network interfaces and all known network
configuration files to avoid address range conflicts. The default system-wide
pool consists of 192.168.0.0/16, 172.16.0.0/12 and 10.0.0.0/8 for IPv4, and
fd00::/8 for IPv6. This functionality is useful to manage a large number of
dynamically created network interfaces with the same network configuration and
automatic address range assignment.
Gateway=
The gateway address, which must be in the
format described in inet_pton(3). This is a short-hand for a [Route]
section only containing a Gateway= key. This option may be specified
more than once.
DNS=
A DNS server address, which must be in the
format described in inet_pton(3). This option may be specified more
than once. Each address can optionally take a port number separated with
":", a network interface name or index separated with "%",
and a Server Name Indication (SNI) separated with "#". When IPv6
address is specified with a port number, then the address must be in the
square brackets. That is, the acceptable full formats are
"111.222.333.444:9953%ifname#example.com" for IPv4 and
"[1111:2222::3333]:9953%ifname#example.com" for IPv6. If an empty
string is assigned, then the all previous assignments are cleared. This
setting is read by systemd-resolved.service(8).
Domains=
A whitespace-separated list of domains which
should be resolved using the DNS servers on this link. Each item in the list
should be a domain name, optionally prefixed with a tilde ("~"). The
domains with the prefix are called "routing-only domains". The
domains without the prefix are called "search domains" and are first
used as search suffixes for extending single-label hostnames (hostnames
containing no dots) to become fully qualified domain names (FQDNs). If a
single-label hostname is resolved on this interface, each of the specified
search domains are appended to it in turn, converting it into a fully
qualified domain name, until one of them may be successfully resolved.
Both "search" and "routing-only" domains are used for
routing of DNS queries: look-ups for hostnames ending in those domains (hence
also single label names, if any "search domains" are listed), are
routed to the DNS servers configured for this interface. The domain routing
logic is particularly useful on multi-homed hosts with DNS servers serving
particular private DNS zones on each interface.
The "routing-only" domain "~." (the tilde indicating
definition of a routing domain, the dot referring to the DNS root domain which
is the implied suffix of all valid DNS names) has special effect. It causes
all DNS traffic which does not match another configured domain routing entry
to be routed to DNS servers specified for this interface. This setting is
useful to prefer a certain set of DNS servers if a link on which they are
connected is available.
This setting is read by systemd-resolved.service(8). "Search
domains" correspond to the domain and search entries in
resolv.conf(5). Domain name routing has no equivalent in the
traditional glibc API, which has no concept of domain name servers limited to
a specific link.
DNSDefaultRoute=
Takes a boolean argument. If true, this link's
configured DNS servers are used for resolving domain names that do not match
any link's configured Domains= setting. If false, this link's
configured DNS servers are never used for such domains, and are exclusively
used for resolving names that match at least one of the domains configured on
this link. If not specified defaults to an automatic mode: queries not
matching any link's configured domains will be routed to this link if it has
no routing-only domains configured.
NTP=
An NTP server address (either an IP address,
or a hostname). This option may be specified more than once. This setting is
read by systemd-timesyncd.service(8).
IPForward=
Configures IP packet forwarding for the
system. If enabled, incoming packets on any network interface will be
forwarded to any other interfaces according to the routing table. Takes a
boolean, or the values "ipv4" or "ipv6", which only enable
IP packet forwarding for the specified address family. This controls the
net.ipv4.ip_forward and net.ipv6.conf.all.forwarding sysctl options of the
network interface (see IP Sysctl[7] for details about sysctl options).
Defaults to "no".
Note: this setting controls a global kernel option, and does so one way only: if
a network that has this setting enabled is set up the global setting is turned
on. However, it is never turned off again, even after all networks with this
setting enabled are shut down again.
To allow IP packet forwarding only between specific network interfaces use a
firewall.
IPMasquerade=
Configures IP masquerading for the network
interface. If enabled, packets forwarded from the network interface will be
appear as coming from the local host. Takes one of "ipv4",
"ipv6", "both", or "no". Defaults to
"no". If enabled, this automatically sets IPForward= to one
of "ipv4", "ipv6" or "yes".
Note. Any positive boolean values such as "yes" or "true"
are now deprecated. Please use one of the values in the above.
IPv6PrivacyExtensions=
Configures use of stateless temporary
addresses that change over time (see RFC 4941[8], Privacy Extensions
for Stateless Address Autoconfiguration in IPv6). Takes a boolean or the
special values "prefer-public" and "kernel". When true,
enables the privacy extensions and prefers temporary addresses over public
addresses. When "prefer-public", enables the privacy extensions, but
prefers public addresses over temporary addresses. When false, the privacy
extensions remain disabled. When "kernel", the kernel's default
setting will be left in place. Defaults to "no".
IPv6AcceptRA=
Takes a boolean. Controls IPv6 Router
Advertisement (RA) reception support for the interface. If true, RAs are
accepted; if false, RAs are ignored. When RAs are accepted, they may trigger
the start of the DHCPv6 client if the relevant flags are set in the RA data,
or if no routers are found on the link. The default is to disable RA reception
for bridge devices or when IP forwarding is enabled, and to enable it
otherwise. Cannot be enabled on bond devices and when link-local addressing is
disabled.
Further settings for the IPv6 RA support may be configured in the [IPv6AcceptRA]
section, see below.
Also see IP Sysctl[7] in the kernel documentation regarding
"accept_ra", but note that systemd's setting of 1 (i.e. true)
corresponds to kernel's setting of 2.
Note that kernel's implementation of the IPv6 RA protocol is always disabled,
regardless of this setting. If this option is enabled, a userspace
implementation of the IPv6 RA protocol is used, and the kernel's own
implementation remains disabled, since systemd-networkd needs to know
all details supplied in the advertisements, and these are not available from
the kernel if the kernel's own implementation is used.
IPv6DuplicateAddressDetection=
Configures the amount of IPv6 Duplicate
Address Detection (DAD) probes to send. When unset, the kernel's default will
be used.
IPv6HopLimit=
Configures IPv6 Hop Limit. For each router
that forwards the packet, the hop limit is decremented by 1. When the hop
limit field reaches zero, the packet is discarded. When unset, the kernel's
default will be used.
IPv4AcceptLocal=
Takes a boolean. Accept packets with local
source addresses. In combination with suitable routing, this can be used to
direct packets between two local interfaces over the wire and have them
accepted properly. When unset, the kernel's default will be used.
IPv4RouteLocalnet=
Takes a boolean. When true, the kernel does
not consider loopback addresses as martian source or destination while
routing. This enables the use of 127.0.0.0/8 for local routing purposes. When
unset, the kernel's default will be used.
IPv4ProxyARP=
Takes a boolean. Configures proxy ARP for
IPv4. Proxy ARP is the technique in which one host, usually a router, answers
ARP requests intended for another machine. By "faking" its identity,
the router accepts responsibility for routing packets to the "real"
destination. See RFC 1027[9]. When unset, the kernel's default will be
used.
IPv6ProxyNDP=
Takes a boolean. Configures proxy NDP for
IPv6. Proxy NDP (Neighbor Discovery Protocol) is a technique for IPv6 to allow
routing of addresses to a different destination when peers expect them to be
present on a certain physical link. In this case a router answers Neighbour
Advertisement messages intended for another machine by offering its own MAC
address as destination. Unlike proxy ARP for IPv4, it is not enabled globally,
but will only send Neighbour Advertisement messages for addresses in the IPv6
neighbor proxy table, which can also be shown by ip -6 neighbour show
proxy. systemd-networkd will control the per-interface `proxy_ndp` switch
for each configured interface depending on this option. When unset, the
kernel's default will be used.
IPv6ProxyNDPAddress=
An IPv6 address, for which Neighbour
Advertisement messages will be proxied. This option may be specified more than
once. systemd-networkd will add the IPv6ProxyNDPAddress= entries to the
kernel's IPv6 neighbor proxy table. This setting implies
IPv6ProxyNDP=yes but has no effect if IPv6ProxyNDP= has been set
to false. When unset, the kernel's default will be used.
IPv6SendRA=
Whether to enable or disable Router
Advertisement sending on a link. Takes a boolean value. When enabled, prefixes
configured in [IPv6Prefix] sections and routes configured in the
[IPv6RoutePrefix] sections are distributed as defined in the [IPv6SendRA]
section. If DHCPPrefixDelegation= is enabled, then the delegated
prefixes are also distributed. See DHCPPrefixDelegation= setting and
the [IPv6SendRA], [IPv6Prefix], [IPv6RoutePrefix], and [DHCPPrefixDelegation]
sections for more configuration options.
DHCPPrefixDelegation=
Takes a boolean value. When enabled, requests
subnet prefixes on another link via the DHCPv6 protocol or via the 6RD option
in the DHCPv4 protocol. An address within each delegated prefix will be
assigned, and the prefixes will be announced through IPv6 Router Advertisement
if IPv6SendRA= is enabled. This behaviour can be configured in the
[DHCPPrefixDelegation] section. Defaults to disabled.
IPv6MTUBytes=
Configures IPv6 maximum transmission unit
(MTU). An integer greater than or equal to 1280 bytes. When unset, the
kernel's default will be used.
KeepMaster=
Takes a boolean value. When enabled, the
current master interface index will not be changed, and
BatmanAdvanced=, Bond=, Bridge=, and VRF= settings
are ignored. This may be useful when a netdev with a master interface is
created by another program, e.g. systemd-nspawn(1). Defaults to
false.
BatmanAdvanced=, Bond=, Bridge=, VRF=
The name of the B.A.T.M.A.N. Advanced, bond,
bridge, or VRF interface to add the link to. See
systemd.netdev(5).
IPoIB=, IPVLAN=, IPVTAP=, MACsec=, MACVLAN=,
MACVTAP=, Tunnel=, VLAN=, VXLAN=, Xfrm=
The name of an IPoIB, IPVLAN, IPVTAP, MACsec,
MACVLAN, MACVTAP, tunnel, VLAN, VXLAN, or Xfrm to be created on the link. See
systemd.netdev(5). This option may be specified more than once.
ActiveSlave=
Takes a boolean. Specifies the new active
slave. The "ActiveSlave=" option is only valid for following modes:
"active-backup", "balance-alb", and
"balance-tlb". Defaults to false.
PrimarySlave=
Takes a boolean. Specifies which slave is the
primary device. The specified device will always be the active slave while it
is available. Only when the primary is off-line will alternate devices be
used. This is useful when one slave is preferred over another, e.g. when one
slave has higher throughput than another. The "PrimarySlave=" option
is only valid for following modes: "active-backup",
"balance-alb", and "balance-tlb". Defaults to false.
ConfigureWithoutCarrier=
Takes a boolean. Allows networkd to configure
a specific link even if it has no carrier. Defaults to false. If enabled, and
the IgnoreCarrierLoss= setting is not explicitly set, then it is
enabled as well.
IgnoreCarrierLoss=
Takes a boolean or a timespan. When true,
systemd-networkd retains both the static and dynamic configuration of
the interface even if its carrier is lost. When false, systemd-networkd
drops both the static and dynamic configuration of the interface. When a
timespan is specified, systemd-networkd waits for the specified
timespan, and ignores the carrier loss if the link regain its carrier within
the timespan. Setting 0 seconds is equivalent to "no", and
"infinite" is equivalent to "yes".
Setting a finite timespan may be useful when e.g. in the following cases:
When Bond= is specified to a wireless interface, defaults to 3 seconds.
When the DHCPv4 client is enabled and UseMTU= in the [DHCPv4] section
enabled, defaults to 5 seconds. Otherwise, defaults to the value specified
with ConfigureWithoutCarrier=. When ActivationPolicy= is set to
"always-up", this is forced to "yes", and ignored any user
specified values.
KeepConfiguration=
•A wireless interface connecting to a
network which has multiple access points with the same SSID.
•Enslaving a wireless interface to a
bond interface, which may disconnect from the connected access point and
causes its carrier to be lost.
•The driver of the interface resets
when the MTU is changed.
Takes a boolean or one of "static",
"dhcp-on-stop", "dhcp". When "static",
systemd-networkd will not drop static addresses and routes on starting
up process. When set to "dhcp-on-stop", systemd-networkd will
not drop addresses and routes on stopping the daemon. When "dhcp",
the addresses and routes provided by a DHCP server will never be dropped even
if the DHCP lease expires. This is contrary to the DHCP specification, but may
be the best choice if, e.g., the root filesystem relies on this connection.
The setting "dhcp" implies "dhcp-on-stop", and
"yes" implies "dhcp" and "static". Defaults to
"dhcp-on-stop" when systemd-networkd is running in initrd,
"yes" when the root filesystem is a network filesystem, and
"no" otherwise.
[ADDRESS] SECTION OPTIONS
An [Address] section accepts the following keys. Specify several [Address] sections to configure several addresses. Address=As in the [Network] section. This setting is
mandatory. Each [Address] section can contain one Address=
setting.
Peer=
The peer address in a point-to-point
connection. Accepts the same format as the Address= setting.
Broadcast=
Takes an IPv4 address or boolean value. The
address must be in the format described in inet_pton(3). If set to
true, then the IPv4 broadcast address will be derived from the Address=
setting. If set to false, then the broadcast address will not be set. Defaults
to true, except for wireguard interfaces, where it default to false.
Label=
Specifies the label for the IPv4 address. The
label must be a 7-bit ASCII string with a length of 1...15 characters.
Defaults to unset.
PreferredLifetime=
Allows the default "preferred
lifetime" of the address to be overridden. Only three settings are
accepted: "forever", "infinity", which is the default and
means that the address never expires, and "0", which means that the
address is considered immediately "expired" and will not be used,
unless explicitly requested. A setting of PreferredLifetime=0 is useful
for addresses which are added to be used only by a specific application, which
is then configured to use them explicitly.
Scope=
The scope of the address, which can be
"global" (valid everywhere on the network, even through a gateway),
"link" (only valid on this device, will not traverse a gateway) or
"host" (only valid within the device itself, e.g. 127.0.0.1) or an
integer in the range 0...255. Defaults to "global".
RouteMetric=
The metric of the prefix route, which is
pointing to the subnet of the configured IP address, taking the configured
prefix length into account. Takes an unsigned integer in the range
0...4294967295. When unset or set to 0, the kernel's default value is used.
This setting will be ignored when AddPrefixRoute= is false.
HomeAddress=
Takes a boolean. Designates this address the
"home address" as defined in RFC 6275[10]. Supported only on
IPv6. Defaults to false.
DuplicateAddressDetection=
Takes one of "ipv4",
"ipv6", "both", or "none". When
"ipv4", performs IPv4 Address Conflict Detection. See RFC
5227[11]. When "ipv6", performs IPv6 Duplicate Address
Detection. See RFC 4862[12]. Defaults to "ipv4" for IPv4
link-local addresses, "ipv6" for IPv6 addresses, and
"none" otherwise.
ManageTemporaryAddress=
Takes a boolean. If true the kernel manage
temporary addresses created from this one as template on behalf of Privacy
Extensions RFC 3041[13]. For this to become active, the use_tempaddr
sysctl setting has to be set to a value greater than zero. The given address
needs to have a prefix length of 64. This flag allows using privacy extensions
in a manually configured network, just like if stateless auto-configuration
was active. Defaults to false.
AddPrefixRoute=
Takes a boolean. When true, the prefix route
for the address is automatically added. Defaults to true.
AutoJoin=
Takes a boolean. Joining multicast group on
ethernet level via ip maddr command would not work if we have an
Ethernet switch that does IGMP snooping since the switch would not replicate
multicast packets on ports that did not have IGMP reports for the multicast
addresses. Linux vxlan interfaces created via ip link add vxlan or
networkd's netdev kind vxlan have the group option that enables them to do the
required join. By extending ip address command with option
"autojoin" we can get similar functionality for openvswitch (OVS)
vxlan interfaces as well as other tunneling mechanisms that need to receive
multicast traffic. Defaults to "no".
NetLabel=label
This setting provides a method for integrating
static and dynamic network configuration into Linux NetLabel[14]
subsystem rules, used by Linux Security Modules (LSMs)[15] for network
access control. The label, with suitable LSM rules, can be used to control
connectivity of (for example) a service with peers in the local network. At
least with SELinux, only the ingress can be controlled but not egress. The
benefit of using this setting is that it may be possible to apply interface
independent part of NetLabel configuration at very early stage of system boot
sequence, at the time when the network interfaces are not available yet, with
netlabelctl(8), and the per-interface configuration with
systemd-networkd once the interfaces appear later. Currently this
feature is only implemented for SELinux.
The option expects a single NetLabel label. The label must conform to lexical
restrictions of LSM labels. When an interface is configured with IP addresses,
the addresses and subnetwork masks will be appended to the NetLabel
Fallback Peer Labeling[16] rules. They will be removed when the interface
is deconfigured. Failures to manage the labels will be ignored.
Warning: Once labeling is enabled for network traffic, a lot of LSM access
control points in Linux networking stack go from dormant to active. Care
should be taken to avoid getting into a situation where for example remote
connectivity is broken, when the security policy hasn't been updated to
consider LSM per-packet access controls and no rules would allow any network
traffic. Also note that additional configuration with netlabelctl(8) is
needed.
Example:
With the example rules applying for interface "eth0", when the
interface is configured with an IPv4 address of 10.0.0.123/8,
systemd-networkd performs the equivalent of netlabelctl
operation
and the reverse operation when the IPv4 address is deconfigured. The
configuration can be used with LSM rules; in case of SELinux to allow a
SELinux domain to receive data from objects of SELinux "peer" class.
For example:
The effect of the above configuration and rules (in absence of other rules as
may be the case) is to only allow "my_server_t" (and nothing else)
to receive data from local subnet 10.0.0.0/8 of interface
"eth0".
[Address] NetLabel=system_u:object_r:localnet_peer_t:s0
netlabelctl unlbl add interface eth0 address:10.0.0.0/8 label:system_u:object_r:localnet_peer_t:s0
type localnet_peer_t; allow my_server_t localnet_peer_t:peer recv;
[NEIGHBOR] SECTION OPTIONS
A [Neighbor] section accepts the following keys. The neighbor section adds a permanent, static entry to the neighbor table (IPv6) or ARP table (IPv4) for the given hardware address on the links matched for the network. Specify several [Neighbor] sections to configure several static neighbors. Address=The IP address of the neighbor.
LinkLayerAddress=
The link layer address (MAC address or IP
address) of the neighbor.
[IPV6ADDRESSLABEL] SECTION OPTIONS
An [IPv6AddressLabel] section accepts the following keys. Specify several [IPv6AddressLabel] sections to configure several address labels. IPv6 address labels are used for address selection. See RFC 3484[17]. Precedence is managed by userspace, and only the label itself is stored in the kernel. Label=The label for the prefix, an unsigned integer
in the range 0...4294967294. 0xffffffff is reserved. This setting is
mandatory.
Prefix=
IPv6 prefix is an address with a prefix
length, separated by a slash "/" character. This setting is
mandatory.
[ROUTINGPOLICYRULE] SECTION OPTIONS
An [RoutingPolicyRule] section accepts the following settings. Specify several [RoutingPolicyRule] sections to configure several rules. TypeOfService=Takes a number between 0 and 255 that
specifies the type of service to match.
From=
Specifies the source address prefix to match.
Possibly followed by a slash and the prefix length.
To=
Specifies the destination address prefix to
match. Possibly followed by a slash and the prefix length.
FirewallMark=
Specifies the iptables firewall mark value to
match (a number in the range 1...4294967295). Optionally, the firewall mask
(also a number between 1...4294967295) can be suffixed with a slash
("/"), e.g., "7/255".
Table=
Specifies the routing table identifier to
lookup if the rule selector matches. Takes one of predefined names
"default", "main", and "local", and names
defined in RouteTable= in networkd.conf(5), or a number between
1 and 4294967295. Defaults to "main".
Priority=
Specifies the priority of this rule.
Priority= is an integer in the range 0...4294967295. Higher number
means lower priority, and rules get processed in order of increasing number.
Defaults to unset, and the kernel will pick a value dynamically.
IncomingInterface=
Specifies incoming device to match. If the
interface is loopback, the rule only matches packets originating from this
host.
OutgoingInterface=
Specifies the outgoing device to match. The
outgoing interface is only available for packets originating from local
sockets that are bound to a device.
SourcePort=
Specifies the source IP port or IP port range
match in forwarding information base (FIB) rules. A port range is specified by
the lower and upper port separated by a dash. Defaults to unset.
DestinationPort=
Specifies the destination IP port or IP port
range match in forwarding information base (FIB) rules. A port range is
specified by the lower and upper port separated by a dash. Defaults to
unset.
IPProtocol=
Specifies the IP protocol to match in
forwarding information base (FIB) rules. Takes IP protocol name such as
"tcp", "udp" or "sctp", or IP protocol number
such as "6" for "tcp" or "17" for
"udp". Defaults to unset.
InvertRule=
A boolean. Specifies whether the rule is to be
inverted. Defaults to false.
Family=
Takes a special value "ipv4",
"ipv6", or "both". By default, the address family is
determined by the address specified in To= or From=. If neither
To= nor From= are specified, then defaults to
"ipv4".
User=
Takes a username, a user ID, or a range of
user IDs separated by a dash. Defaults to unset.
SuppressPrefixLength=
Takes a number N in the range 0...128
and rejects routing decisions that have a prefix length of N or less.
Defaults to unset.
SuppressInterfaceGroup=
Takes an integer in the range 0...2147483647
and rejects routing decisions that have an interface with the same group id.
It has the same meaning as suppress_ifgroup in ip rule. Defaults
to unset.
Type=
Specifies Routing Policy Database (RPDB) rule
type. Takes one of "blackhole", "unreachable" or
"prohibit".
[NEXTHOP] SECTION OPTIONS
The [NextHop] section is used to manipulate entries in the kernel's "nexthop" tables. The [NextHop] section accepts the following settings. Specify several [NextHop] sections to configure several hops. Id=The id of the next hop. Takes an integer in
the range 1...4294967295. If unspecified, then automatically chosen by
kernel.
Gateway=
As in the [Network] section.
Family=
Takes one of the special values
"ipv4" or "ipv6". By default, the family is determined by
the address specified in Gateway=. If Gateway= is not specified,
then defaults to "ipv4".
OnLink=
Takes a boolean. If set to true, the kernel
does not have to check if the gateway is reachable directly by the current
machine (i.e., attached to the local network), so that we can insert the
nexthop in the kernel table without it being complained about. Defaults to
"no".
Blackhole=
Takes a boolean. If enabled, packets to the
corresponding routes are discarded silently, and Gateway= cannot be
specified. Defaults to "no".
Group=
Takes a whitespace separated list of nexthop
IDs. Each ID must be in the range 1...4294967295. Optionally, each nexthop ID
can take a weight after a colon (" id[:weight]"). The
weight must be in the range 1...255. If the weight is not specified, then it
is assumed that the weight is 1. This setting cannot be specified with
Gateway=, Family=, Blackhole=. This setting can be
specified multiple times. If an empty string is assigned, then the all
previous assignments are cleared. Defaults to unset.
[ROUTE] SECTION OPTIONS
The [Route] section accepts the following settings. Specify several [Route] sections to configure several routes. Gateway=Takes the gateway address or the special
values "_dhcp4" and "_ipv6ra". If "_dhcp4" or
"_ipv6ra" is set, then the gateway address provided by DHCPv4 or
IPv6 RA is used.
GatewayOnLink=
Takes a boolean. If set to true, the kernel
does not have to check if the gateway is reachable directly by the current
machine (i.e., attached to the local network), so that we can insert the route
in the kernel table without it being complained about. Defaults to
"no".
Destination=
The destination prefix of the route. Possibly
followed by a slash and the prefix length. If omitted, a full-length host
route is assumed.
Source=
The source prefix of the route. Possibly
followed by a slash and the prefix length. If omitted, a full-length host
route is assumed.
Metric=
The metric of the route. Takes an unsigned
integer in the range 0...4294967295. Defaults to unset, and the kernel's
default will be used.
IPv6Preference=
Specifies the route preference as defined in
RFC 4191[18] for Router Discovery messages. Which can be one of
"low" the route has a lowest priority, "medium" the route
has a default priority or "high" the route has a highest
priority.
Scope=
The scope of the IPv4 route, which can be
"global", "site", "link", "host", or
"nowhere":
For IPv4 route, defaults to "host" if Type= is
"local" or "nat", and "link" if Type= is
"broadcast", "multicast", "anycast", or
"unicast". In other cases, defaults to "global". The value
is not used for IPv6.
PreferredSource=
•"global" means the route can
reach hosts more than one hop away.
•"site" means an interior
route in the local autonomous system.
•"link" means the route can
only reach hosts on the local network (one hop away).
•"host" means the route will
not leave the local machine (used for internal addresses like
127.0.0.1).
•"nowhere" means the
destination doesn't exist.
The preferred source address of the route. The
address must be in the format described in inet_pton(3).
Table=
The table identifier for the route. Takes one
of predefined names "default", "main", and
"local", and names defined in RouteTable= in
networkd.conf(5), or a number between 1 and 4294967295. The table can
be retrieved using ip route show table num. If unset and
Type= is "local", "broadcast", "anycast",
or "nat", then "local" is used. In other cases, defaults
to "main".
Protocol=
The protocol identifier for the route. Takes a
number between 0 and 255 or the special values "kernel",
"boot", "static", "ra" and "dhcp".
Defaults to "static".
Type=
Specifies the type for the route. Takes one of
"unicast", "local", "broadcast",
"anycast", "multicast", "blackhole",
"unreachable", "prohibit", "throw",
"nat", and "xresolve". If "unicast", a regular
route is defined, i.e. a route indicating the path to take to a destination
network address. If "blackhole", packets to the defined route are
discarded silently. If "unreachable", packets to the defined route
are discarded and the ICMP message "Host Unreachable" is generated.
If "prohibit", packets to the defined route are discarded and the
ICMP message "Communication Administratively Prohibited" is
generated. If "throw", route lookup in the current routing table
will fail and the route selection process will return to Routing Policy
Database (RPDB). Defaults to "unicast".
InitialCongestionWindow=
The TCP initial congestion window is used
during the start of a TCP connection. During the start of a TCP session, when
a client requests a resource, the server's initial congestion window
determines how many packets will be sent during the initial burst of data
without waiting for acknowledgement. Takes a number between 1 and 1023. Note
that 100 is considered an extremely large value for this option. When unset,
the kernel's default (typically 10) will be used.
InitialAdvertisedReceiveWindow=
The TCP initial advertised receive window is
the amount of receive data (in bytes) that can initially be buffered at one
time on a connection. The sending host can send only that amount of data
before waiting for an acknowledgment and window update from the receiving
host. Takes a number between 1 and 1023. Note that 100 is considered an
extremely large value for this option. When unset, the kernel's default will
be used.
QuickAck=
Takes a boolean. When true enables TCP quick
ack mode for the route. When unset, the kernel's default will be used.
FastOpenNoCookie=
Takes a boolean. When true enables TCP
fastopen without a cookie on a per-route basis. When unset, the kernel's
default will be used.
TTLPropagate=
Takes a boolean. When true enables TTL
propagation at Label Switched Path (LSP) egress. When unset, the kernel's
default will be used.
MTUBytes=
The maximum transmission unit in bytes to set
for the route. The usual suffixes K, M, G, are supported and are understood to
the base of 1024.
TCPAdvertisedMaximumSegmentSize=
Specifies the Path MSS (in bytes) hints given
on TCP layer. The usual suffixes K, M, G, are supported and are understood to
the base of 1024. An unsigned integer in the range 1...4294967294. When unset,
the kernel's default will be used.
TCPCongestionControlAlgorithm=
Specifies the TCP congestion control algorithm
for the route. Takes a name of the algorithm, e.g. "bbr",
"dctcp", or "vegas". When unset, the kernel's default will
be used.
MultiPathRoute=address[@name]
[weight]
Configures multipath route. Multipath routing
is the technique of using multiple alternative paths through a network. Takes
gateway address. Optionally, takes a network interface name or index separated
with "@", and a weight in 1..256 for this multipath route separated
with whitespace. This setting can be specified multiple times. If an empty
string is assigned, then the all previous assignments are cleared.
NextHop=
Specifies the nexthop id. Takes an unsigned
integer in the range 1...4294967295. If set, the corresponding [NextHop]
section must be configured. Defaults to unset.
[DHCPV4] SECTION OPTIONS
The [DHCPv4] section configures the DHCPv4 client, if it is enabled with the DHCP= setting described above: SendHostname=When true (the default), the machine's
hostname (or the value specified with Hostname=, described below) will
be sent to the DHCP server. Note that the hostname must consist only of 7-bit
ASCII lower-case characters and no spaces or dots, and be formatted as a valid
DNS domain name. Otherwise, the hostname is not sent even if this option is
true.
Hostname=
Use this value for the hostname which is sent
to the DHCP server, instead of machine's hostname. Note that the specified
hostname must consist only of 7-bit ASCII lower-case characters and no spaces
or dots, and be formatted as a valid DNS domain name.
MUDURL=
When configured, the specified Manufacturer
Usage Description (MUD) URL will be sent to the DHCPv4 server. Takes a URL of
length up to 255 characters. A superficial verification that the string is a
valid URL will be performed. DHCPv4 clients are intended to have at most one
MUD URL associated with them. See RFC 8520[19].
MUD is an embedded software standard defined by the IETF that allows IoT device
makers to advertise device specifications, including the intended
communication patterns for their device when it connects to the network. The
network can then use this to author a context-specific access policy, so the
device functions only within those parameters.
ClientIdentifier=
The DHCPv4 client identifier to use. Takes one
of mac, duid or duid-only. If set to mac, the MAC
address of the link is used. If set to duid, an RFC4361-compliant
Client ID, which is the combination of IAID and DUID (see below), is used. If
set to duid-only, only DUID is used, this may not be RFC compliant, but
some setups may require to use this. Defaults to duid.
VendorClassIdentifier=
The vendor class identifier used to identify
vendor type and configuration.
UserClass=
A DHCPv4 client can use UserClass option to
identify the type or category of user or applications it represents. The
information contained in this option is a string that represents the user
class of which the client is a member. Each class sets an identifying string
of information to be used by the DHCP service to classify clients. Takes a
whitespace-separated list of strings.
DUIDType=
Override the global DUIDType= setting
for this network. See networkd.conf(5) for a description of possible
values.
DUIDRawData=
Override the global DUIDRawData=
setting for this network. See networkd.conf(5) for a description of
possible values.
IAID=
The DHCP Identity Association Identifier
(IAID) for the interface, a 32-bit unsigned integer.
Anonymize=
Takes a boolean. When true, the options sent
to the DHCP server will follow the RFC 7844[20] (Anonymity Profiles for
DHCP Clients) to minimize disclosure of identifying information. Defaults to
false.
This option should only be set to true when MACAddressPolicy= is set to
random (see systemd.link(5)).
When true, ClientIdentifier=mac, SendHostname=no,
Use6RD=no, UseCaptivePortal=no, UseMTU=no,
UseNTP=no, UseSIP=no, and UseTimezone=no are implied and
these settings in the .network file are silently ignored. Also,
Hostname=, MUDURL=, RequestOptions=, SendOption=,
SendVendorOption=, UserClass=, and VendorClassIdentifier=
are silently ignored.
With this option enabled DHCP requests will mimic those generated by Microsoft
Windows, in order to reduce the ability to fingerprint and recognize
installations. This means DHCP request sizes will grow and lease data will be
more comprehensive than normally, though most of the requested data is not
actually used.
RequestOptions=
Sets request options to be sent to the server
in the DHCPv4 request options list. A whitespace-separated list of integers in
the range 1...254. Defaults to unset.
SendOption=
Send an arbitrary raw option in the DHCPv4
request. Takes a DHCP option number, data type and data separated with a colon
(" option:type:value"). The option number must
be an integer in the range 1...254. The type takes one of "uint8",
"uint16", "uint32", "ipv4address", or
"string". Special characters in the data string may be escaped using
C-style escapes[21]. This setting can be specified multiple times. If
an empty string is specified, then all options specified earlier are cleared.
Defaults to unset.
SendVendorOption=
Send an arbitrary vendor option in the DHCPv4
request. Takes a DHCP option number, data type and data separated with a colon
(" option:type:value"). The option number must
be an integer in the range 1...254. The type takes one of "uint8",
"uint16", "uint32", "ipv4address", or
"string". Special characters in the data string may be escaped using
C-style escapes[21]. This setting can be specified multiple times. If
an empty string is specified, then all options specified earlier are cleared.
Defaults to unset.
IPServiceType=
Takes one of the special values
"none", "CS6", or "CS4". When "none"
no IP service type is set to the packet sent from the DHCPv4 client. When
"CS6" (network control) or "CS4" (realtime), the
corresponding service type will be set. Defaults to "CS6".
Label=
Specifies the label for the IPv4 address
received from the DHCP server. The label must be a 7-bit ASCII string with a
length of 1...15 characters. Defaults to unset.
UseDNS=
When true (the default), the DNS servers
received from the DHCP server will be used.
This corresponds to the nameserver option in resolv.conf(5).
RoutesToDNS=
When true, the routes to the DNS servers
received from the DHCP server will be configured. When UseDNS= is
disabled, this setting is ignored. Defaults to true.
UseNTP=
When true (the default), the NTP servers
received from the DHCP server will be used by systemd-timesyncd.service.
RoutesToNTP=
When true, the routes to the NTP servers
received from the DHCP server will be configured. When UseNTP= is
disabled, this setting is ignored. Defaults to true.
UseSIP=
When true (the default), the SIP servers
received from the DHCP server will be collected and made available to client
programs.
UseMTU=
When true, the interface maximum transmission
unit from the DHCP server will be used on the current link. If
MTUBytes= is set, then this setting is ignored. Defaults to false.
Note, some drivers will reset the interfaces if the MTU is changed. For such
interfaces, please try to use IgnoreCarrierLoss= with a short timespan,
e.g. "3 seconds".
UseHostname=
When true (the default), the hostname received
from the DHCP server will be set as the transient hostname of the
system.
UseDomains=
Takes a boolean, or the special value
route. When true, the domain name received from the DHCP server will be
used as DNS search domain over this link, similarly to the effect of the
Domains= setting. If set to route, the domain name received from
the DHCP server will be used for routing DNS queries only, but not for
searching, similarly to the effect of the Domains= setting when the
argument is prefixed with "~". Defaults to false.
It is recommended to enable this option only on trusted networks, as setting
this affects resolution of all hostnames, in particular of single-label names.
It is generally safer to use the supplied domain only as routing domain,
rather than as search domain, in order to not have it affect local resolution
of single-label names.
When set to true, this setting corresponds to the domain option in
resolv.conf(5).
UseRoutes=
When true (the default), the static routes
will be requested from the DHCP server and added to the routing table with a
metric of 1024, and a scope of global, link or host,
depending on the route's destination and gateway. If the destination is on the
local host, e.g., 127.x.x.x, or the same as the link's own address, the scope
will be set to host. Otherwise if the gateway is null (a direct route),
a link scope will be used. For anything else, scope defaults to
global.
RouteMetric=
Set the routing metric for routes specified by
the DHCP server (including the prefix route added for the specified prefix).
Takes an unsigned integer in the range 0...4294967295. Defaults to 1024.
RouteTable=num
The table identifier for DHCP routes. Takes
one of predefined names "default", "main", and
"local", and names defined in RouteTable= in
networkd.conf(5), or a number between 1...4294967295.
When used in combination with VRF=, the VRF's routing table is used when
this parameter is not specified.
RouteMTUBytes=
Specifies the MTU for the DHCP routes. Please
see the [Route] section for further details.
UseGateway=
When true, the gateway will be requested from
the DHCP server and added to the routing table with a metric of 1024, and a
scope of link. When unset, the value specified with UseRoutes=
is used.
UseTimezone=
When true, the timezone received from the DHCP
server will be set as timezone of the local system. Defaults to false.
Use6RD=
When true, subnets of the received IPv6 prefix
are assigned to downstream interfaces which enables
DHCPPrefixDelegation=. See also DHCPPrefixDelegation= in the
[Network] section, the [DHCPPrefixDelegation] section, and RFC
5969[22]. Defaults to false.
FallbackLeaseLifetimeSec=
Allows one to set DHCPv4 lease lifetime when
DHCPv4 server does not send the lease lifetime. Takes one of
"forever" or "infinity". If specified, the acquired
address never expires. Defaults to unset.
RequestBroadcast=
Request the server to use broadcast messages
before the IP address has been configured. This is necessary for devices that
cannot receive RAW packets, or that cannot receive packets at all before an IP
address has been configured. On the other hand, this must not be enabled on
networks where broadcasts are filtered out.
MaxAttempts=
Specifies how many times the DHCPv4 client
configuration should be attempted. Takes a number or "infinity".
Defaults to "infinity". Note that the time between retries is
increased exponentially, up to approximately one per minute, so the network
will not be overloaded even if this number is high. The default is suitable in
most circumstances.
ListenPort=
Set the port from which the DHCP client
packets originate.
DenyList=
A whitespace-separated list of IPv4 addresses.
Each address can optionally take a prefix length after "/". DHCP
offers from servers in the list are rejected. Note that if AllowList=
is configured then DenyList= is ignored.
AllowList=
A whitespace-separated list of IPv4 addresses.
Each address can optionally take a prefix length after "/". DHCP
offers from servers in the list are accepted.
SendRelease=
When true, the DHCPv4 client sends a DHCP
release packet when it stops. Defaults to true.
SendDecline=
A boolean. When true, systemd-networkd
performs IPv4 Duplicate Address Detection to the acquired address by the
DHCPv4 client. If duplicate is detected, the DHCPv4 client rejects the address
by sending a DHCPDECLINE packet to the DHCP server, and tries to obtain
an IP address again. See RFC 5227[11]. Defaults to false.
NetLabel=
This applies the NetLabel for the addresses
received with DHCP, like NetLabel= in [Address] section applies it to
statically configured addresses. See NetLabel= in [Address] section for
more details.
[DHCPV6] SECTION OPTIONS
The [DHCPv6] section configures the DHCPv6 client, if it is enabled with the DHCP= setting described above, or invoked by the IPv6 Router Advertisement: MUDURL=, IAID=, DUIDType=, DUIDRawData=, RequestOptions=As in the [DHCPv4] section.
SendOption=
As in the [DHCPv4] section, however because
DHCPv6 uses 16-bit fields to store option numbers, the option number is an
integer in the range 1...65536.
SendVendorOption=
Send an arbitrary vendor option in the DHCPv6
request. Takes an enterprise identifier, DHCP option number, data type, and
data separated with a colon (" enterprise
identifier:option: type:value"). Enterprise
identifier is an unsigned integer in the range 1...4294967294. The option
number must be an integer in the range 1...254. Data type takes one of
"uint8", "uint16", "uint32",
"ipv4address", "ipv6address", or "string".
Special characters in the data string may be escaped using C-style
escapes[21]. This setting can be specified multiple times. If an empty
string is specified, then all options specified earlier are cleared. Defaults
to unset.
UserClass=
A DHCPv6 client can use User Class option to
identify the type or category of user or applications it represents. The
information contained in this option is a string that represents the user
class of which the client is a member. Each class sets an identifying string
of information to be used by the DHCP service to classify clients. Special
characters in the data string may be escaped using C-style escapes[21].
This setting can be specified multiple times. If an empty string is specified,
then all options specified earlier are cleared. Takes a whitespace-separated
list of strings. Note that currently NUL bytes are not allowed.
VendorClass=
A DHCPv6 client can use VendorClass option to
identify the vendor that manufactured the hardware on which the client is
running. The information contained in the data area of this option is
contained in one or more opaque fields that identify details of the hardware
configuration. Takes a whitespace-separated list of strings.
PrefixDelegationHint=
Takes an IPv6 address with prefix length in
the same format as the Address= in the [Network] section. The DHCPv6
client will include a prefix hint in the DHCPv6 solicitation sent to the
server. The prefix length must be in the range 1...128. Defaults to
unset.
RapidCommit=
Takes a boolean. The DHCPv6 client can obtain
configuration parameters from a DHCPv6 server through a rapid two-message
exchange (solicit and reply). When the rapid commit option is set by both the
DHCPv6 client and the DHCPv6 server, the two-message exchange is used.
Otherwise, the four-message exchange (solicit, advertise, request, and reply)
is used. The two-message exchange provides faster client configuration. See
RFC 3315[23] for details. Defaults to true, and the two-message
exchange will be used if the server support it.
UseAddress=
When true (the default), the IP addresses
provided by the DHCPv6 server will be assigned.
UseDelegatedPrefix=
When true (the default), the client will
request the DHCPv6 server to delegate prefixes. If the server provides
prefixes to be delegated, then subnets of the prefixes are assigned to the
interfaces that have DHCPPrefixDelegation=yes. See also the
DHCPPrefixDelegation= setting in the [Network] section, settings in the
[DHCPPrefixDelegation] section, and RFC 8415[24].
UseDNS=, UseNTP=, UseHostname=, UseDomains=,
NetLabel=
As in the [DHCPv4] section.
WithoutRA=
Allows DHCPv6 client to start without router
advertisements's "managed" or "other configuration" flag.
Takes one of "no", "solicit", or
"information-request". If this is not specified, "solicit"
is used when DHCPPrefixDelegation= is enabled and
UplinkInterface=:self is specified in the [DHCPPrefixDelegation]
section. Otherwise, defaults to "no", and the DHCPv6 client will be
started when an RA is received. See also the DHCPv6Client= setting in
the [IPv6AcceptRA] section.
[DHCPPREFIXDELEGATION] SECTION OPTIONS
The [DHCPPrefixDelegation] section configures subnet prefixes of the delegated prefixes acquired by a DHCPv6 client, or by a DHCPv4 client through the 6RD option on another interface. The settings in this section are used only when the DHCPPrefixDelegation= setting in the [Network] section is enabled. UplinkInterface=Specifies the name or the index of the uplink
interface, or one of the special values ":self" and
":auto". When ":self", the interface itself is considered
the uplink interface, and WithoutRA=solicit is implied if the setting
is not explicitly specified. When ":auto", the first link which
acquired prefixes to be delegated from the DHCPv6 or DHCPv4 server is
selected. Defaults to ":auto".
SubnetId=
Configure a specific subnet ID on the
interface from a (previously) received prefix delegation. You can either set
"auto" (the default) or a specific subnet ID (as defined in RFC
4291[25], section 2.5.4), in which case the allowed value is hexadecimal,
from 0 to 0x7fffffffffffffff inclusive.
Announce=
Takes a boolean. When enabled, and
IPv6SendRA= in [Network] section is enabled, the delegated prefixes are
distributed through the IPv6 Router Advertisement. This setting will be
ignored when the DHCPPrefixDelegation= setting is enabled on the
upstream interface. Defaults to yes.
Assign=
Takes a boolean. Specifies whether to add an
address from the delegated prefixes which are received from the WAN interface
by the DHCPv6 Prefix Delegation. When true (on LAN interfce), the EUI-64
algorithm will be used by default to form an interface identifier from the
delegated prefixes. See also Token= setting below. Defaults to
yes.
Token=
Specifies an optional address generation mode
for assigning an address in each delegated prefix. This accepts the same
syntax as Token= in the [IPv6AcceptRA] section. If Assign= is
set to false, then this setting will be ignored. Defaults to unset, which
means the EUI-64 algorithm will be used.
ManageTemporaryAddress=
As in the [Address] section, but defaults to
true.
RouteMetric=
The metric of the route to the delegated
prefix subnet. Takes an unsigned integer in the range 0...4294967295. When set
to 0, the kernel's default value is used. Defaults to 256.
NetLabel=
This applies the NetLabel for the addresses
received with DHCP, like NetLabel= in [Address] section applies it to
statically configured addresses. See NetLabel= in [Address] section for
more details.
[IPV6ACCEPTRA] SECTION OPTIONS
The [IPv6AcceptRA] section configures the IPv6 Router Advertisement (RA) client, if it is enabled with the IPv6AcceptRA= setting described above: Token=Specifies an optional address generation mode
for the Stateless Address Autoconfiguration (SLAAC). The following values are
supported:
eui64
If no address generation mode is specified (which is the default), or a received
prefix does not match any of the addresses provided in
"prefixstable" mode, then the EUI-64 algorithm will be used for
Ethernet or InfiniBand interfaces, otherwise "prefixstable" will be
used to form an interface identifier for that prefix.
This setting can be specified multiple times. If an empty string is assigned,
then the all previous assignments are cleared.
Examples:
UseDNS=
The EUI-64 algorithm will be used to generate
an address for that prefix. Only supported by Ethernet or InfiniBand
interfaces.
static:ADDRESS
An IPv6 address must be specified after a
colon (":"), and the lower bits of the supplied address are combined
with the upper bits of a prefix received in a Router Advertisement (RA)
message to form a complete address. Note that if multiple prefixes are
received in an RA message, or in multiple RA messages, addresses will be
formed from each of them using the supplied address. This mode implements
SLAAC but uses a static interface identifier instead of an identifier
generated by using the EUI-64 algorithm. Because the interface identifier is
static, if Duplicate Address Detection detects that the computed address is a
duplicate (in use by another node on the link), then this mode will fail to
provide an address for that prefix. If an IPv6 address without mode is
specified, then "static" mode is assumed.
prefixstable[:ADDRESS][,UUID]
The algorithm specified in RFC 7217[26]
will be used to generate interface identifiers. This mode can optionally take
an IPv6 address separated with a colon (":"). If an IPv6 address is
specified, then an interface identifier is generated only when a prefix
received in an RA message matches the supplied address.
This mode can also optionally take a non-null UUID in the format which
sd_id128_from_string() accepts, e.g.
"86b123b969ba4b7eb8b3d8605123525a" or
"86b123b9-69ba-4b7e-b8b3-d8605123525a". If a UUID is specified, the
value is used as the secret key to generate interface identifiers. If not
specified, then an application specific ID generated with the system's
machine-ID will be used as the secret key. See sd-id128(3),
sd_id128_from_string(3), and sd_id128_get_machine(3).
Note that the "prefixstable" algorithm uses both the interface name
and MAC address as input to the hash to compute the interface identifier, so
if either of those are changed the resulting interface identifier (and
address) will be changed, even if the prefix received in the RA message has
not been changed.
Token=eui64 Token=::1a:2b:3c:4d Token=static:::1a:2b:3c:4d Token=prefixstable Token=prefixstable:2002:da8:1::
When true (the default), the DNS servers
received in the Router Advertisement will be used.
This corresponds to the nameserver option in resolv.conf(5).
UseDomains=
Takes a boolean, or the special value
"route". When true, the domain name received via IPv6 Router
Advertisement (RA) will be used as DNS search domain over this link, similarly
to the effect of the Domains= setting. If set to "route", the
domain name received via IPv6 RA will be used for routing DNS queries only,
but not for searching, similarly to the effect of the Domains= setting
when the argument is prefixed with "~". Defaults to false.
It is recommended to enable this option only on trusted networks, as setting
this affects resolution of all hostnames, in particular of single-label names.
It is generally safer to use the supplied domain only as routing domain,
rather than as search domain, in order to not have it affect local resolution
of single-label names.
When set to true, this setting corresponds to the domain option in
resolv.conf(5).
RouteTable=num
The table identifier for the routes received
in the Router Advertisement. Takes one of predefined names
"default", "main", and "local", and names
defined in RouteTable= in networkd.conf(5), or a number between
1...4294967295.
When used in combination with VRF=, the VRF's routing table is used when
this parameter is not specified.
RouteMetric=
Set the routing metric for the routes received
in the Router Advertisement. Takes an unsigned integer in the range
0...4294967295. Defaults to 1024.
UseMTU=
Takes a boolean. When true, the MTU received
in the Router Advertisement will be used. Defaults to true.
UseGateway=
When true (the default), the router address
will be configured as the default gateway.
UseRoutePrefix=
When true (the default), the routes
corresponding to the route prefixes received in the Router Advertisement will
be configured.
UseAutonomousPrefix=
When true (the default), the autonomous prefix
received in the Router Advertisement will be used and take precedence over any
statically configured ones.
UseOnLinkPrefix=
When true (the default), the onlink prefix
received in the Router Advertisement will be used and takes precedence over
any statically configured ones.
RouterDenyList=
A whitespace-separated list of IPv6 router
addresses. Each address can optionally take a prefix length after
"/". Any information advertised by the listed router is
ignored.
RouterAllowList=
A whitespace-separated list of IPv6 router
addresses. Each address can optionally take a prefix length after
"/". Only information advertised by the listed router is accepted.
Note that if RouterAllowList= is configured then RouterDenyList=
is ignored.
PrefixDenyList=
A whitespace-separated list of IPv6 prefixes.
Each prefix can optionally take its prefix length after "/". IPv6
prefixes supplied via router advertisements in the list are ignored.
PrefixAllowList=
A whitespace-separated list of IPv6 prefixes.
Each prefix can optionally take its prefix length after "/". IPv6
prefixes supplied via router advertisements in the list are allowed. Note that
if PrefixAllowList= is configured then PrefixDenyList= is
ignored.
RouteDenyList=
A whitespace-separated list of IPv6 route
prefixes. Each prefix can optionally take its prefix length after
"/". IPv6 route prefixes supplied via router advertisements in the
list are ignored.
RouteAllowList=
A whitespace-separated list of IPv6 route
prefixes. Each prefix can optionally take its prefix length after
"/". IPv6 route prefixes supplied via router advertisements in the
list are allowed. Note that if RouteAllowList= is configured then
RouteDenyList= is ignored.
DHCPv6Client=
Takes a boolean, or the special value
"always". When true, the DHCPv6 client will be started in
"solicit" mode if the RA has the "managed" flag or
"information-request" mode if the RA lacks the "managed"
flag but has the "other configuration" flag. If set to
"always", the DHCPv6 client will be started in "solicit"
mode when an RA is received, even if neither the "managed" nor the
"other configuration" flag is set in the RA. This will be ignored
when WithoutRA= in the [DHCPv6] section is enabled, or
UplinkInterface=:self in the [DHCPPrefixDelegation] section is
specified. Defaults to true.
NetLabel=
This applies the NetLabel for the addresses
received with RA, like NetLabel= in [Address] section applies it to
statically configured addresses. See NetLabel= in [Address] section for
more details.
[DHCPSERVER] SECTION OPTIONS
The [DHCPServer] section contains settings for the DHCP server, if enabled via the DHCPServer= option described above: ServerAddress=Specifies server address for the DHCP server.
Takes an IPv4 address with prefix length, for example 192.168.0.1/24. This
setting may be useful when the link on which the DHCP server is running has
multiple static addresses. When unset, one of static addresses in the link
will be automatically selected. Defaults to unset.
PoolOffset=, PoolSize=
Configures the pool of addresses to hand out.
The pool is a contiguous sequence of IP addresses in the subnet configured for
the server address, which does not include the subnet nor the broadcast
address. PoolOffset= takes the offset of the pool from the start of
subnet, or zero to use the default value. PoolSize= takes the number of
IP addresses in the pool or zero to use the default value. By default, the
pool starts at the first address after the subnet address and takes up the
rest of the subnet, excluding the broadcast address. If the pool includes the
server address (the default), this is reserved and not handed out to
clients.
DefaultLeaseTimeSec=, MaxLeaseTimeSec=
Control the default and maximum DHCP lease
time to pass to clients. These settings take time values in seconds or another
common time unit, depending on the suffix. The default lease time is used for
clients that did not ask for a specific lease time. If a client asks for a
lease time longer than the maximum lease time, it is automatically shortened
to the specified time. The default lease time defaults to 1h, the maximum
lease time to 12h. Shorter lease times are beneficial if the configuration
data in DHCP leases changes frequently and clients shall learn the new
settings with shorter latencies. Longer lease times reduce the generated DHCP
network traffic.
UplinkInterface=
Specifies the name or the index of the uplink
interface, or one of the special values ":none" and
":auto". When emitting DNS, NTP, or SIP servers is enabled but no
servers are specified, the servers configured in the uplink interface will be
emitted. When ":auto", the link which has a default gateway with the
highest priority will be automatically selected. When ":none", no
uplink interface will be selected. Defaults to ":auto".
EmitDNS=, DNS=
EmitDNS= takes a boolean. Configures
whether the DHCP leases handed out to clients shall contain DNS server
information. Defaults to "yes". The DNS servers to pass to clients
may be configured with the DNS= option, which takes a list of IPv4
addresses, or special value "_server_address" which will be
converted to the address used by the DHCP server.
If the EmitDNS= option is enabled but no servers configured, the servers
are automatically propagated from an "uplink" interface that has
appropriate servers set. The "uplink" interface is determined by the
default route of the system with the highest priority. Note that this
information is acquired at the time the lease is handed out, and does not take
uplink interfaces into account that acquire DNS server information at a later
point. If no suitable uplink interface is found the DNS server data from
/etc/resolv.conf is used. Also, note that the leases are not refreshed if the
uplink network configuration changes. To ensure clients regularly acquire the
most current uplink DNS server information, it is thus advisable to shorten
the DHCP lease time via MaxLeaseTimeSec= described above.
This setting can be specified multiple times. If an empty string is specified,
then all DNS servers specified earlier are cleared.
EmitNTP=, NTP=, EmitSIP=, SIP=, EmitPOP3=,
POP3=, EmitSMTP=, SMTP=, EmitLPR=, LPR=
Similar to the EmitDNS= and DNS=
settings described above, these settings configure whether and what server
information for the indicate protocol shall be emitted as part of the DHCP
lease. The same syntax, propagation semantics and defaults apply as for
EmitDNS= and DNS=.
EmitRouter=, Router=
The EmitRouter= setting takes a boolean
value, and configures whether the DHCP lease should contain the router option.
The Router= setting takes an IPv4 address, and configures the router
address to be emitted. When the Router= setting is not specified, then
the server address will be used for the router option. When the
EmitRouter= setting is disabled, the Router= setting will be
ignored. The EmitRouter= setting defaults to true, and the
Router= setting defaults to unset.
EmitTimezone=, Timezone=
Takes a boolean. Configures whether the DHCP
leases handed out to clients shall contain timezone information. Defaults to
"yes". The Timezone= setting takes a timezone string (such as
"Europe/Berlin" or "UTC") to pass to clients. If no
explicit timezone is set, the system timezone of the local host is propagated,
as determined by the /etc/localtime symlink.
BootServerAddress=
Takes an IPv4 address of the boot server used
by e.g. PXE boot systems. When specified, this address is sent in the
siaddr field of the DHCP message header. See RFC 2131[27] for
more details. Defaults to unset.
BootServerName=
Takes a name of the boot server used by e.g.
PXE boot systems. When specified, this name is sent in the DHCP option 66
("TFTP server name"). See RFC 2132[28] for more details.
Defaults to unset.
Note that typically setting one of BootServerName= or
BootServerAddress= is sufficient, but both can be set too, if
desired.
BootFilename=
Takes a path or URL to a file loaded by e.g. a
PXE boot loader. When specified, this path is sent in the DHCP option 67
("Bootfile name"). See RFC 2132[28] for more details.
Defaults to unset.
SendOption=
Send a raw option with value via DHCPv4
server. Takes a DHCP option number, data type and data ("
option:type:value"). The option number is an integer
in the range 1...254. The type takes one of "uint8",
"uint16", "uint32", "ipv4address",
"ipv6address", or "string". Special characters in the data
string may be escaped using C-style escapes[21]. This setting can be
specified multiple times. If an empty string is specified, then all options
specified earlier are cleared. Defaults to unset.
SendVendorOption=
Send a vendor option with value via DHCPv4
server. Takes a DHCP option number, data type and data ("
option:type:value"). The option number is an integer
in the range 1...254. The type takes one of "uint8",
"uint16", "uint32", "ipv4address", or
"string". Special characters in the data string may be escaped using
C-style escapes[21]. This setting can be specified multiple times. If
an empty string is specified, then all options specified earlier are cleared.
Defaults to unset.
BindToInterface=
Takes a boolean value. When "yes",
DHCP server socket will be bound to its network interface and all socket
communication will be restricted to this interface. Defaults to
"yes", except if RelayTarget= is used (see below), in which
case it defaults to "no".
RelayTarget=
Takes an IPv4 address, which must be in the
format described in inet_pton(3). Turns this DHCP server into a DHCP
relay agent. See RFC 1542[29]. The address is the address of DHCP
server or another relay agent to forward DHCP messages to and from.
RelayAgentCircuitId=
Specifies value for Agent Circuit ID suboption
of Relay Agent Information option. Takes a string, which must be in the format
"string: value", where " value" should be
replaced with the value of the suboption. Defaults to unset (means no Agent
Circuit ID suboption is generated). Ignored if RelayTarget= is not
specified.
RelayAgentRemoteId=
Specifies value for Agent Remote ID suboption
of Relay Agent Information option. Takes a string, which must be in the format
"string: value", where " value" should be
replaced with the value of the suboption. Defaults to unset (means no Agent
Remote ID suboption is generated). Ignored if RelayTarget= is not
specified.
[DHCPSERVERSTATICLEASE] SECTION OPTIONS
The "[DHCPServerStaticLease]" section configures a static DHCP lease to assign a fixed IPv4 address to a specific device based on its MAC address. This section can be specified multiple times. MACAddress=The hardware address of a device to match.
This key is mandatory.
Address=
The IPv4 address that should be assigned to
the device that was matched with MACAddress=. This key is
mandatory.
[IPV6SENDRA] SECTION OPTIONS
The [IPv6SendRA] section contains settings for sending IPv6 Router Advertisements and whether to act as a router, if enabled via the IPv6SendRA= option described above. IPv6 network prefixes or routes are defined with one or more [IPv6Prefix] or [IPv6RoutePrefix] sections. Managed=, OtherInformation=Takes a boolean. Controls whether a DHCPv6
server is used to acquire IPv6 addresses on the network link when
Managed= is set to "true" or if only additional network
information can be obtained via DHCPv6 for the network link when
OtherInformation= is set to "true". Both settings default to
"false", which means that a DHCPv6 server is not being used.
RouterLifetimeSec=
Takes a timespan. Configures the IPv6 router
lifetime in seconds. The value must be 0 seconds, or between 4 seconds and
9000 seconds. When set to 0, the host is not acting as a router. Defaults to
1800 seconds (30 minutes).
RouterPreference=
Configures IPv6 router preference if
RouterLifetimeSec= is non-zero. Valid values are "high",
"medium" and "low", with "normal" and
"default" added as synonyms for "medium" just to make
configuration easier. See RFC 4191[18] for details. Defaults to
"medium".
UplinkInterface=
Specifies the name or the index of the uplink
interface, or one of the special values ":none" and
":auto". When emitting DNS servers or search domains is enabled but
no servers are specified, the servers configured in the uplink interface will
be emitted. When ":auto", the value specified to the same setting in
the [DHCPPrefixDelegation] section will be used if
DHCPPrefixDelegation= is enabled, otherwise the link which has a
default gateway with the highest priority will be automatically selected. When
":none", no uplink interface will be selected. Defaults to
":auto".
EmitDNS=, DNS=
DNS= specifies a list of recursive DNS
server IPv6 addresses that are distributed via Router Advertisement messages
when EmitDNS= is true. DNS= also takes special value
"_link_local"; in that case the IPv6 link-local address is
distributed. If DNS= is empty, DNS servers are read from the [Network]
section. If the [Network] section does not contain any DNS servers either, DNS
servers from the uplink interface specified in UplinkInterface= will be
used. When EmitDNS= is false, no DNS server information is sent in
Router Advertisement messages. EmitDNS= defaults to true.
EmitDomains=, Domains=
A list of DNS search domains distributed via
Router Advertisement messages when EmitDomains= is true. If
Domains= is empty, DNS search domains are read from the [Network]
section. If the [Network] section does not contain any DNS search domains
either, DNS search domains from the uplink interface specified in
UplinkInterface= will be used. When EmitDomains= is false, no
DNS search domain information is sent in Router Advertisement messages.
EmitDomains= defaults to true.
DNSLifetimeSec=
Lifetime in seconds for the DNS server
addresses listed in DNS= and search domains listed in Domains=.
Defaults to 3600 seconds (one hour).
[IPV6PREFIX] SECTION OPTIONS
One or more [IPv6Prefix] sections contain the IPv6 prefixes that are announced via Router Advertisements. See RFC 4861[30] for further details. AddressAutoconfiguration=, OnLink=Takes a boolean to specify whether IPv6
addresses can be autoconfigured with this prefix and whether the prefix can be
used for onlink determination. Both settings default to "true" in
order to ease configuration.
Prefix=
The IPv6 prefix that is to be distributed to
hosts. Similarly to configuring static IPv6 addresses, the setting is
configured as an IPv6 prefix and its prefix length, separated by a
"/" character. Use multiple [IPv6Prefix] sections to configure
multiple IPv6 prefixes since prefix lifetimes, address autoconfiguration and
onlink status may differ from one prefix to another.
PreferredLifetimeSec=, ValidLifetimeSec=
Preferred and valid lifetimes for the prefix
measured in seconds. PreferredLifetimeSec= defaults to 1800 seconds (30
minutes) and ValidLifetimeSec= defaults to 3600 seconds (one
hour).
Assign=
Takes a boolean. When true, adds an address
from the prefix. Default to false.
Token=
Specifies an optional address generation mode
for assigning an address in each prefix. This accepts the same syntax as
Token= in the [IPv6AcceptRA] section. If Assign= is set to
false, then this setting will be ignored. Defaults to unset, which means the
EUI-64 algorithm will be used.
RouteMetric=
The metric of the prefix route. Takes an
unsigned integer in the range 0...4294967295. When unset or set to 0, the
kernel's default value is used. This setting is ignored when Assign= is
false.
[IPV6ROUTEPREFIX] SECTION OPTIONS
One or more [IPv6RoutePrefix] sections contain the IPv6 prefix routes that are announced via Router Advertisements. See RFC 4191[18] for further details. Route=The IPv6 route that is to be distributed to
hosts. Similarly to configuring static IPv6 routes, the setting is configured
as an IPv6 prefix routes and its prefix route length, separated by a
"/" character. Use multiple [IPv6RoutePrefix] sections to configure
multiple IPv6 prefix routes.
LifetimeSec=
Lifetime for the route prefix measured in
seconds. LifetimeSec= defaults to 3600 seconds (one hour).
[BRIDGE] SECTION OPTIONS
The [Bridge] section accepts the following keys: UnicastFlood=Takes a boolean. Controls whether the bridge
should flood traffic for which an FDB entry is missing and the destination is
unknown through this port. When unset, the kernel's default will be
used.
MulticastFlood=
Takes a boolean. Controls whether the bridge
should flood traffic for which an MDB entry is missing and the destination is
unknown through this port. When unset, the kernel's default will be
used.
MulticastToUnicast=
Takes a boolean. Multicast to unicast works on
top of the multicast snooping feature of the bridge. Which means unicast
copies are only delivered to hosts which are interested in it. When unset, the
kernel's default will be used.
NeighborSuppression=
Takes a boolean. Configures whether ARP and ND
neighbor suppression is enabled for this port. When unset, the kernel's
default will be used.
Learning=
Takes a boolean. Configures whether MAC
address learning is enabled for this port. When unset, the kernel's default
will be used.
HairPin=
Takes a boolean. Configures whether traffic
may be sent back out of the port on which it was received. When this flag is
false, then the bridge will not forward traffic back out of the receiving
port. When unset, the kernel's default will be used.
Isolated=
Takes a boolean. Configures whether this port
is isolated or not. Within a bridge, isolated ports can only communicate with
non-isolated ports. When set to true, this port can only communicate with
other ports whose Isolated setting is false. When set to false, this port can
communicate with any other ports. When unset, the kernel's default will be
used.
UseBPDU=
Takes a boolean. Configures whether STP Bridge
Protocol Data Units will be processed by the bridge port. When unset, the
kernel's default will be used.
FastLeave=
Takes a boolean. This flag allows the bridge
to immediately stop multicast traffic on a port that receives an IGMP Leave
message. It is only used with IGMP snooping if enabled on the bridge. When
unset, the kernel's default will be used.
AllowPortToBeRoot=
Takes a boolean. Configures whether a given
port is allowed to become a root port. Only used when STP is enabled on the
bridge. When unset, the kernel's default will be used.
ProxyARP=
Takes a boolean. Configures whether proxy ARP
to be enabled on this port. When unset, the kernel's default will be
used.
ProxyARPWiFi=
Takes a boolean. Configures whether proxy ARP
to be enabled on this port which meets extended requirements by IEEE 802.11
and Hotspot 2.0 specifications. When unset, the kernel's default will be
used.
MulticastRouter=
Configures this port for having multicast
routers attached. A port with a multicast router will receive all multicast
traffic. Takes one of "no" to disable multicast routers on this
port, "query" to let the system detect the presence of routers,
"permanent" to permanently enable multicast traffic forwarding on
this port, or "temporary" to enable multicast routers temporarily on
this port, not depending on incoming queries. When unset, the kernel's default
will be used.
Cost=
Sets the "cost" of sending packets
of this interface. Each port in a bridge may have a different speed and the
cost is used to decide which link to use. Faster interfaces should have lower
costs. It is an integer value between 1 and 65535.
Priority=
Sets the "priority" of sending
packets on this interface. Each port in a bridge may have a different priority
which is used to decide which link to use. Lower value means higher priority.
It is an integer value between 0 to 63. Networkd does not set any default,
meaning the kernel default value of 32 is used.
[BRIDGEFDB] SECTION OPTIONS
The [BridgeFDB] section manages the forwarding database table of a port and accepts the following keys. Specify several [BridgeFDB] sections to configure several static MAC table entries. MACAddress=As in the [Network] section. This key is
mandatory.
Destination=
Takes an IP address of the destination VXLAN
tunnel endpoint.
VLANId=
The VLAN ID for the new static MAC table
entry. If omitted, no VLAN ID information is appended to the new static MAC
table entry.
VNI=
The VXLAN Network Identifier (or VXLAN Segment
ID) to use to connect to the remote VXLAN tunnel endpoint. Takes a number in
the range 1...16777215. Defaults to unset.
AssociatedWith=
Specifies where the address is associated
with. Takes one of "use", "self", "master" or
"router". "use" means the address is in use. User space
can use this option to indicate to the kernel that the fdb entry is in use.
"self" means the address is associated with the port drivers fdb.
Usually hardware. "master" means the address is associated with
master devices fdb. "router" means the destination address is
associated with a router. Note that it's valid if the referenced device is a
VXLAN type device and has route shortcircuit enabled. Defaults to
"self".
OutgoingInterface=
Specifies the name or index of the outgoing
interface for the VXLAN device driver to reach the remote VXLAN tunnel
endpoint. Defaults to unset.
[BRIDGEMDB] SECTION OPTIONS
The [BridgeMDB] section manages the multicast membership entries forwarding database table of a port and accepts the following keys. Specify several [BridgeMDB] sections to configure several permanent multicast membership entries. MulticastGroupAddress=Specifies the IPv4 or IPv6 multicast group
address to add. This setting is mandatory.
VLANId=
The VLAN ID for the new entry. Valid ranges
are 0 (no VLAN) to 4094. Optional, defaults to 0.
[LLDP] SECTION OPTIONS
The [LLDP] section manages the Link Layer Discovery Protocol (LLDP) and accepts the following keys: MUDURL=When configured, the specified Manufacturer
Usage Descriptions (MUD) URL will be sent in LLDP packets. The syntax and
semantics are the same as for MUDURL= in the [DHCPv4] section described
above.
The MUD URLs received via LLDP packets are saved and can be read using the
sd_lldp_neighbor_get_mud_url() function.
[CAN] SECTION OPTIONS
The [CAN] section manages the Controller Area Network (CAN bus) and accepts the following keys: BitRate=The bitrate of CAN device in bits per second.
The usual SI prefixes (K, M) with the base of 1000 can be used here. Takes a
number in the range 1...4294967295.
SamplePoint=
Optional sample point in percent with one
decimal (e.g. "75%", "87.5%") or permille (e.g.
"875‰"). This will be ignored when BitRate= is
unspecified.
TimeQuantaNSec=, PropagationSegment=, PhaseBufferSegment1=,
PhaseBufferSegment2=, SyncJumpWidth=
Specifies the time quanta, propagation
segment, phase buffer segment 1 and 2, and the synchronization jump width,
which allow one to define the CAN bit-timing in a hardware independent format
as proposed by the Bosch CAN 2.0 Specification. TimeQuantaNSec= takes a
timespan in nanoseconds. PropagationSegment=,
PhaseBufferSegment1=, PhaseBufferSegment2=, and
SyncJumpWidth= take number of time quantum specified in
TimeQuantaNSec= and must be an unsigned integer in the range
0...4294967295. These settings except for SyncJumpWidth= will be
ignored when BitRate= is specified.
DataBitRate=, DataSamplePoint=
The bitrate and sample point for the data
phase, if CAN-FD is used. These settings are analogous to the BitRate=
and SamplePoint= keys.
DataTimeQuantaNSec=, DataPropagationSegment=,
DataPhaseBufferSegment1=, DataPhaseBufferSegment2=,
DataSyncJumpWidth=
Specifies the time quanta, propagation
segment, phase buffer segment 1 and 2, and the synchronization jump width for
the data phase, if CAN-FD is used. These settings are analogous to the
TimeQuantaNSec= or related settings.
FDMode=
Takes a boolean. When "yes", CAN-FD
mode is enabled for the interface. Note, that a bitrate and optional sample
point should also be set for the CAN-FD data phase using the
DataBitRate= and DataSamplePoint= keys, or
DataTimeQuanta= and related settings.
FDNonISO=
Takes a boolean. When "yes", non-ISO
CAN-FD mode is enabled for the interface. When unset, the kernel's default
will be used.
RestartSec=
Automatic restart delay time. If set to a
non-zero value, a restart of the CAN controller will be triggered
automatically in case of a bus-off condition after the specified delay time.
Subsecond delays can be specified using decimals (e.g. "0.1s") or a
"ms" or "us" postfix. Using "infinity" or
"0" will turn the automatic restart off. By default automatic
restart is disabled.
Termination=
Takes a boolean or a termination resistor
value in ohm in the range 0...65535. When "yes", the termination
resistor is set to 120 ohm. When "no" or "0" is set, the
termination resistor is disabled. When unset, the kernel's default will be
used.
TripleSampling=
Takes a boolean. When "yes", three
samples (instead of one) are used to determine the value of a received bit by
majority rule. When unset, the kernel's default will be used.
BusErrorReporting=
Takes a boolean. When "yes",
reporting of CAN bus errors is activated (those include single bit, frame
format, and bit stuffing errors, unable to send dominant bit, unable to send
recessive bit, bus overload, active error announcement, error occurred on
transmission). When unset, the kernel's default will be used. Note: in case of
a CAN bus with a single CAN device, sending a CAN frame may result in a huge
number of CAN bus errors.
ListenOnly=
Takes a boolean. When "yes",
listen-only mode is enabled. When the interface is in listen-only mode, the
interface neither transmit CAN frames nor send ACK bit. Listen-only mode is
important to debug CAN networks without interfering with the communication or
acknowledge the CAN frame. When unset, the kernel's default will be
used.
Loopback=
Takes a boolean. When "yes",
loopback mode is enabled. When the loopback mode is enabled, the interface
treats messages transmitted by itself as received messages. The loopback mode
is important to debug CAN networks. When unset, the kernel's default will be
used.
OneShot=
Takes a boolean. When "yes",
one-shot mode is enabled. When unset, the kernel's default will be used.
PresumeAck=
Takes a boolean. When "yes", the
interface will ignore missing CAN ACKs. When unset, the kernel's default will
be used.
ClassicDataLengthCode=
Takes a boolean. When "yes", the
interface will handle the 4bit data length code (DLC). When unset, the
kernel's default will be used.
[IPOIB] SECTION OPTIONS
The [IPoIB] section manages the IP over Infiniband and accepts the following keys: Mode=Takes one of the special values
"datagram" or "connected". Defaults to unset, and the
kernel's default is used.
When "datagram", the Infiniband unreliable datagram (UD) transport is
used, and so the interface MTU is equal to the IB L2 MTU minus the IPoIB
encapsulation header (4 bytes). For example, in a typical IB fabric with a 2K
MTU, the IPoIB MTU will be 2048 - 4 = 2044 bytes.
When "connected", the Infiniband reliable connected (RC) transport is
used. Connected mode takes advantage of the connected nature of the IB
transport and allows an MTU up to the maximal IP packet size of 64K, which
reduces the number of IP packets needed for handling large UDP datagrams, TCP
segments, etc and increases the performance for large messages.
IgnoreUserspaceMulticastGroup=
Takes an boolean value. When true, the kernel
ignores multicast groups handled by userspace. Defaults to unset, and the
kernel's default is used.
[QDISC] SECTION OPTIONS
The [QDisc] section manages the traffic control queueing discipline (qdisc). Parent=Specifies the parent Queueing Discipline
(qdisc). Takes one of "clsact" or "ingress". This is
mandatory.
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
[NETWORKEMULATOR] SECTION OPTIONS
The [NetworkEmulator] section manages the queueing discipline (qdisc) of the network emulator. It can be used to configure the kernel packet scheduler and simulate packet delay and loss for UDP or TCP applications, or limit the bandwidth usage of a particular service to simulate internet connections. Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
DelaySec=
Specifies the fixed amount of delay to be
added to all packets going out of the interface. Defaults to unset.
DelayJitterSec=
Specifies the chosen delay to be added to the
packets outgoing to the network interface. Defaults to unset.
PacketLimit=
Specifies the maximum number of packets the
qdisc may hold queued at a time. An unsigned integer in the range
0...4294967294. Defaults to 1000.
LossRate=
Specifies an independent loss probability to
be added to the packets outgoing from the network interface. Takes a
percentage value, suffixed with "%". Defaults to unset.
DuplicateRate=
Specifies that the chosen percent of packets
is duplicated before queuing them. Takes a percentage value, suffixed with
"%". Defaults to unset.
[TOKENBUCKETFILTER] SECTION OPTIONS
The [TokenBucketFilter] section manages the queueing discipline (qdisc) of token bucket filter (tbf). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
LatencySec=
Specifies the latency parameter, which
specifies the maximum amount of time a packet can sit in the Token Bucket
Filter (TBF). Defaults to unset.
LimitBytes=
Takes the number of bytes that can be queued
waiting for tokens to become available. When the size is suffixed with K, M,
or G, it is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the
base of 1024. Defaults to unset.
BurstBytes=
Specifies the size of the bucket. This is the
maximum amount of bytes that tokens can be available for instantaneous
transfer. When the size is suffixed with K, M, or G, it is parsed as
Kilobytes, Megabytes, or Gigabytes, respectively, to the base of 1024.
Defaults to unset.
Rate=
Specifies the device specific bandwidth. When
suffixed with K, M, or G, the specified bandwidth is parsed as Kilobits,
Megabits, or Gigabits, respectively, to the base of 1000. Defaults to
unset.
MPUBytes=
The Minimum Packet Unit (MPU) determines the
minimal token usage (specified in bytes) for a packet. When suffixed with K,
M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
respectively, to the base of 1024. Defaults to zero.
PeakRate=
Takes the maximum depletion rate of the
bucket. When suffixed with K, M, or G, the specified size is parsed as
Kilobits, Megabits, or Gigabits, respectively, to the base of 1000. Defaults
to unset.
MTUBytes=
Specifies the size of the peakrate bucket.
When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
Megabytes, or Gigabytes, respectively, to the base of 1024. Defaults to
unset.
[PIE] SECTION OPTIONS
The [PIE] section manages the queueing discipline (qdisc) of Proportional Integral controller-Enhanced (PIE). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the queue size in
number of packets. When this limit is reached, incoming packets are dropped.
An unsigned integer in the range 1...4294967294. Defaults to unset and
kernel's default is used.
[FLOWQUEUEPIE] SECTION OPTIONS
The "[FlowQueuePIE]" section manages the queueing discipline (qdisc) of Flow Queue Proportional Integral controller-Enhanced (fq_pie). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the queue size in
number of packets. When this limit is reached, incoming packets are dropped.
An unsigned integer ranges 1 to 4294967294. Defaults to unset and kernel's
default is used.
[STOCHASTICFAIRBLUE] SECTION OPTIONS
The [StochasticFairBlue] section manages the queueing discipline (qdisc) of stochastic fair blue (sfb). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the queue size in
number of packets. When this limit is reached, incoming packets are dropped.
An unsigned integer in the range 0...4294967294. Defaults to unset and
kernel's default is used.
[STOCHASTICFAIRNESSQUEUEING] SECTION OPTIONS
The [StochasticFairnessQueueing] section manages the queueing discipline (qdisc) of stochastic fairness queueing (sfq). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
PerturbPeriodSec=
Specifies the interval in seconds for queue
algorithm perturbation. Defaults to unset.
[BFIFO] SECTION OPTIONS
The [BFIFO] section manages the queueing discipline (qdisc) of Byte limited Packet First In First Out (bfifo). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
LimitBytes=
Specifies the hard limit in bytes on the FIFO
buffer size. The size limit prevents overflow in case the kernel is unable to
dequeue packets as quickly as it receives them. When this limit is reached,
incoming packets are dropped. When suffixed with K, M, or G, the specified
size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the
base of 1024. Defaults to unset and kernel default is used.
[PFIFO] SECTION OPTIONS
The [PFIFO] section manages the queueing discipline (qdisc) of Packet First In First Out (pfifo). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the number of
packets in the FIFO queue. The size limit prevents overflow in case the kernel
is unable to dequeue packets as quickly as it receives them. When this limit
is reached, incoming packets are dropped. An unsigned integer in the range
0...4294967294. Defaults to unset and kernel's default is used.
[PFIFOHEADDROP] SECTION OPTIONS
The [PFIFOHeadDrop] section manages the queueing discipline (qdisc) of Packet First In First Out Head Drop (pfifo_head_drop). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
PacketLimit=
As in [PFIFO] section.
[PFIFOFAST] SECTION OPTIONS
The [PFIFOFast] section manages the queueing discipline (qdisc) of Packet First In First Out Fast (pfifo_fast). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
[CAKE] SECTION OPTIONS
The [CAKE] section manages the queueing discipline (qdisc) of Common Applications Kept Enhanced (CAKE). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
Bandwidth=
Specifies the shaper bandwidth. When suffixed
with K, M, or G, the specified size is parsed as Kilobits, Megabits, or
Gigabits, respectively, to the base of 1000. Defaults to unset and kernel's
default is used.
AutoRateIngress=
Takes a boolean value. Enables automatic
capacity estimation based on traffic arriving at this qdisc. This is most
likely to be useful with cellular links, which tend to change quality
randomly. If this setting is enabled, the Bandwidth= setting is used as
an initial estimate. Defaults to unset, and the kernel's default is
used.
OverheadBytes=
Specifies that bytes to be addeded to the size
of each packet. Bytes may be negative. Takes an integer in the range
-64...256. Defaults to unset and kernel's default is used.
MPUBytes=
Rounds each packet (including overhead) up to
the specified bytes. Takes an integer in the range 1...256. Defaults to unset
and kernel's default is used.
CompensationMode=
Takes one of "none",
"atm", or "ptm". Specifies the compensation mode for
overhead calculation. When "none", no compensation is taken into
account. When "atm", enables the compensation for ATM cell framing,
which is normally found on ADSL links. When "ptm", enables the
compensation for PTM encoding, which is normally found on VDSL2 links and uses
a 64b/65b encoding scheme. Defaults to unset and the kernel's default is
used.
UseRawPacketSize=
Takes a boolean value. When true, the packet
size reported by the Linux kernel will be used, instead of the underlying IP
packet size. Defaults to unset, and the kernel's default is used.
FlowIsolationMode=
CAKE places packets from different flows into
different queues, then packets from each queue are delivered fairly. This
specifies whether the fairness is based on source address, destination
address, individual flows, or any combination of those. The available values
are:
none
Defaults to unset and the kernel's default is used.
NAT=
The flow isolation is disabled, and all
traffic passes through a single queue.
src-host
Flows are defined only by source address.
Equivalent to the "srchost" option for tc qdisc command. See
also tc-cake(8).
dst-host
Flows are defined only by destination address.
Equivalent to the "dsthost" option for tc qdisc command. See
also tc-cake(8).
hosts
Flows are defined by source-destination host
pairs. Equivalent to the same option for tc qdisc command. See also
tc-cake(8).
flows
Flows are defined by the entire 5-tuple of
source address, destination address, transport protocol, source port and
destination port. Equivalent to the same option for tc qdisc command.
See also tc-cake(8).
dual-src-host
Flows are defined by the 5-tuple (see
"flows" in the above), and fairness is applied first over source
addresses, then over individual flows. Equivalent to the
"dual-srchost" option for tc qdisc command. See also
tc-cake(8).
dual-dst-host
Flows are defined by the 5-tuple (see
"flows" in the above), and fairness is applied first over
destination addresses, then over individual flows. Equivalent to the
"dual-dsthost" option for tc qdisc command. See also
tc-cake(8).
triple
Flows are defined by the 5-tuple (see
"flows"), and fairness is applied over source and destination
addresses, and also over individual flows. Equivalent to the
"triple-isolate" option for tc qdisc command. See also
tc-cake(8).
Takes a boolean value. When true, CAKE
performs a NAT lookup before applying flow-isolation rules, to determine the
true addresses and port numbers of the packet, to improve fairness between
hosts inside the NAT. This has no practical effect when
FlowIsolationMode= is "none" or "flows", or if NAT
is performed on a different host. Defaults to unset, and the kernel's default
is used.
PriorityQueueingPreset=
CAKE divides traffic into "tins",
and each tin has its own independent set of flow-isolation queues, bandwidth
threshold, and priority. This specifies the preset of tin profiles. The
available values are:
besteffort
Defaults to unset, and the kernel's default is used.
FirewallMark=
Disables priority queueing by placing all
traffic in one tin.
precedence
Enables priority queueing based on the legacy
interpretation of TOS "Precedence" field. Use of this preset on the
modern Internet is firmly discouraged.
diffserv8
Enables priority queueing based on the
Differentiated Service ("DiffServ") field with eight tins:
Background Traffic, High Throughput, Best Effort, Video Streaming, Low Latency
Transactions, Interactive Shell, Minimum Latency, and Network Control.
diffserv4
Enables priority queueing based on the
Differentiated Service ("DiffServ") field with four tins: Background
Traffic, Best Effort, Streaming Media, and Latency Sensitive.
diffserv3
Enables priority queueing based on the
Differentiated Service ("DiffServ") field with three tins:
Background Traffic, Best Effort, and Latency Sensitive.
Takes an integer in the range 1...4294967295.
When specified, firewall-mark-based overriding of CAKE's tin selection is
enabled. Defaults to unset, and the kernel's default is used.
Wash=
Takes a boolean value. When true, CAKE clears
the DSCP fields, except for ECN bits, of any packet passing through CAKE.
Defaults to unset, and the kernel's default is used.
SplitGSO=
Takes a boolean value. When true, CAKE will
split General Segmentation Offload (GSO) super-packets into their on-the-wire
components and dequeue them individually. Defaults to unset, and the kernel's
default is used.
[CONTROLLEDDELAY] SECTION OPTIONS
The [ControlledDelay] section manages the queueing discipline (qdisc) of controlled delay (CoDel). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the queue size in
number of packets. When this limit is reached, incoming packets are dropped.
An unsigned integer in the range 0...4294967294. Defaults to unset and
kernel's default is used.
TargetSec=
Takes a timespan. Specifies the acceptable
minimum standing/persistent queue delay. Defaults to unset and kernel's
default is used.
IntervalSec=
Takes a timespan. This is used to ensure that
the measured minimum delay does not become too stale. Defaults to unset and
kernel's default is used.
ECN=
Takes a boolean. This can be used to mark
packets instead of dropping them. Defaults to unset and kernel's default is
used.
CEThresholdSec=
Takes a timespan. This sets a threshold above
which all packets are marked with ECN Congestion Experienced (CE). Defaults to
unset and kernel's default is used.
[DEFICITROUNDROBINSCHEDULER] SECTION OPTIONS
The [DeficitRoundRobinScheduler] section manages the queueing discipline (qdisc) of Deficit Round Robin Scheduler (DRR). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
[DEFICITROUNDROBINSCHEDULERCLASS] SECTION OPTIONS
The [DeficitRoundRobinSchedulerClass] section manages the traffic control class of Deficit Round Robin Scheduler (DRR). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", or a qdisc identifier. The qdisc
identifier is specified as the major and minor numbers in hexadecimal in the
range 0x1–Oxffff separated with a colon ("major:minor").
Defaults to "root".
ClassId=
Configures the unique identifier of the class.
It is specified as the major and minor numbers in hexadecimal in the range
0x1–Oxffff separated with a colon ("major:minor"). Defaults
to unset.
QuantumBytes=
Specifies the amount of bytes a flow is
allowed to dequeue before the scheduler moves to the next class. When suffixed
with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or
Gigabytes, respectively, to the base of 1024. Defaults to the MTU of the
interface.
[ENHANCEDTRANSMISSIONSELECTION] SECTION OPTIONS
The [EnhancedTransmissionSelection] section manages the queueing discipline (qdisc) of Enhanced Transmission Selection (ETS). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
Bands=
Specifies the number of bands. An unsigned
integer in the range 1...16. This value has to be at least large enough to
cover the strict bands specified through the StrictBands= and
bandwidth-sharing bands specified in QuantumBytes=.
StrictBands=
Specifies the number of bands that should be
created in strict mode. An unsigned integer in the range 1...16.
QuantumBytes=
Specifies the white-space separated list of
quantum used in band-sharing bands. When suffixed with K, M, or G, the
specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively,
to the base of 1024. This setting can be specified multiple times. If an empty
string is assigned, then the all previous assignments are cleared.
PriorityMap=
The priority map maps the priority of a packet
to a band. The argument is a whitespace separated list of numbers. The first
number indicates which band the packets with priority 0 should be put to, the
second is for priority 1, and so on. There can be up to 16 numbers in the
list. If there are fewer, the default band that traffic with one of the
unmentioned priorities goes to is the last one. Each band number must be in
the range 0...255. This setting can be specified multiple times. If an empty
string is assigned, then the all previous assignments are cleared.
[GENERICRANDOMEARLYDETECTION] SECTION OPTIONS
The [GenericRandomEarlyDetection] section manages the queueing discipline (qdisc) of Generic Random Early Detection (GRED). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
VirtualQueues=
Specifies the number of virtual queues. Takes
an integer in the range 1...16. Defaults to unset and kernel's default is
used.
DefaultVirtualQueue=
Specifies the number of default virtual queue.
This must be less than VirtualQueue=. Defaults to unset and kernel's
default is used.
GenericRIO=
Takes a boolean. It turns on the RIO-like
buffering scheme. Defaults to unset and kernel's default is used.
[FAIRQUEUEINGCONTROLLEDDELAY] SECTION OPTIONS
The [FairQueueingControlledDelay] section manages the queueing discipline (qdisc) of fair queuing controlled delay (FQ-CoDel). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the real queue
size. When this limit is reached, incoming packets are dropped. Defaults to
unset and kernel's default is used.
MemoryLimitBytes=
Specifies the limit on the total number of
bytes that can be queued in this FQ-CoDel instance. When suffixed with K, M,
or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
respectively, to the base of 1024. Defaults to unset and kernel's default is
used.
Flows=
Specifies the number of flows into which the
incoming packets are classified. Defaults to unset and kernel's default is
used.
TargetSec=
Takes a timespan. Specifies the acceptable
minimum standing/persistent queue delay. Defaults to unset and kernel's
default is used.
IntervalSec=
Takes a timespan. This is used to ensure that
the measured minimum delay does not become too stale. Defaults to unset and
kernel's default is used.
QuantumBytes=
Specifies the number of bytes used as the
"deficit" in the fair queuing algorithm timespan. When suffixed with
K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or
Gigabytes, respectively, to the base of 1024. Defaults to unset and kernel's
default is used.
ECN=
Takes a boolean. This can be used to mark
packets instead of dropping them. Defaults to unset and kernel's default is
used.
CEThresholdSec=
Takes a timespan. This sets a threshold above
which all packets are marked with ECN Congestion Experienced (CE). Defaults to
unset and kernel's default is used.
[FAIRQUEUEING] SECTION OPTIONS
The [FairQueueing] section manages the queueing discipline (qdisc) of fair queue traffic policing (FQ). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the real queue
size. When this limit is reached, incoming packets are dropped. Defaults to
unset and kernel's default is used.
FlowLimit=
Specifies the hard limit on the maximum number
of packets queued per flow. Defaults to unset and kernel's default is
used.
QuantumBytes=
Specifies the credit per dequeue RR round,
i.e. the amount of bytes a flow is allowed to dequeue at once. When suffixed
with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or
Gigabytes, respectively, to the base of 1024. Defaults to unset and kernel's
default is used.
InitialQuantumBytes=
Specifies the initial sending rate credit,
i.e. the amount of bytes a new flow is allowed to dequeue initially. When
suffixed with K, M, or G, the specified size is parsed as Kilobytes,
Megabytes, or Gigabytes, respectively, to the base of 1024. Defaults to unset
and kernel's default is used.
MaximumRate=
Specifies the maximum sending rate of a flow.
When suffixed with K, M, or G, the specified size is parsed as Kilobits,
Megabits, or Gigabits, respectively, to the base of 1000. Defaults to unset
and kernel's default is used.
Buckets=
Specifies the size of the hash table used for
flow lookups. Defaults to unset and kernel's default is used.
OrphanMask=
Takes an unsigned integer. For packets not
owned by a socket, fq is able to mask a part of hash and reduce number of
buckets associated with the traffic. Defaults to unset and kernel's default is
used.
Pacing=
Takes a boolean, and enables or disables flow
pacing. Defaults to unset and kernel's default is used.
CEThresholdSec=
Takes a timespan. This sets a threshold above
which all packets are marked with ECN Congestion Experienced (CE). Defaults to
unset and kernel's default is used.
[TRIVIALLINKEQUALIZER] SECTION OPTIONS
The [TrivialLinkEqualizer] section manages the queueing discipline (qdisc) of trivial link equalizer (teql). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
Id=
Specifies the interface ID "N" of
teql. Defaults to "0". Note that when teql is used, currently, the
module sch_teql with max_equalizers=N+1 option must be loaded
before systemd-networkd is started.
[HIERARCHYTOKENBUCKET] SECTION OPTIONS
The [HierarchyTokenBucket] section manages the queueing discipline (qdisc) of hierarchy token bucket (htb). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
DefaultClass=
Takes the minor id in hexadecimal of the
default class. Unclassified traffic gets sent to the class. Defaults to
unset.
RateToQuantum=
Takes an unsigned integer. The DRR quantums
are calculated by dividing the value configured in Rate= by
RateToQuantum=.
[HIERARCHYTOKENBUCKETCLASS] SECTION OPTIONS
The [HierarchyTokenBucketClass] section manages the traffic control class of hierarchy token bucket (htb). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", or a qdisc identifier. The qdisc
identifier is specified as the major and minor numbers in hexadecimal in the
range 0x1–Oxffff separated with a colon ("major:minor").
Defaults to "root".
ClassId=
Configures the unique identifier of the class.
It is specified as the major and minor numbers in hexadecimal in the range
0x1–Oxffff separated with a colon ("major:minor"). Defaults
to unset.
Priority=
Specifies the priority of the class. In the
round-robin process, classes with the lowest priority field are tried for
packets first.
QuantumBytes=
Specifies how many bytes to serve from leaf at
once. When suffixed with K, M, or G, the specified size is parsed as
Kilobytes, Megabytes, or Gigabytes, respectively, to the base of 1024.
MTUBytes=
Specifies the maximum packet size we create.
When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
Megabytes, or Gigabytes, respectively, to the base of 1024.
OverheadBytes=
Takes an unsigned integer which specifies
per-packet size overhead used in rate computations. When suffixed with K, M,
or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
respectively, to the base of 1024.
Rate=
Specifies the maximum rate this class and all
its children are guaranteed. When suffixed with K, M, or G, the specified size
is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000. This setting is mandatory.
CeilRate=
Specifies the maximum rate at which a class
can send, if its parent has bandwidth to spare. When suffixed with K, M, or G,
the specified size is parsed as Kilobits, Megabits, or Gigabits, respectively,
to the base of 1000. When unset, the value specified with Rate= is
used.
BufferBytes=
Specifies the maximum bytes burst which can be
accumulated during idle period. When suffixed with K, M, or G, the specified
size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the
base of 1024.
CeilBufferBytes=
Specifies the maximum bytes burst for ceil
which can be accumulated during idle period. When suffixed with K, M, or G,
the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
respectively, to the base of 1024.
[HEAVYHITTERFILTER] SECTION OPTIONS
The [HeavyHitterFilter] section manages the queueing discipline (qdisc) of Heavy Hitter Filter (hhf). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the queue size in
number of packets. When this limit is reached, incoming packets are dropped.
An unsigned integer in the range 0...4294967294. Defaults to unset and
kernel's default is used.
[QUICKFAIRQUEUEING] SECTION OPTIONS
The [QuickFairQueueing] section manages the queueing discipline (qdisc) of Quick Fair Queueing (QFQ). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", "clsact",
"ingress" or a class identifier. The class identifier is specified
as the major and minor numbers in hexadecimal in the range 0x1–Oxffff
separated with a colon ("major:minor"). Defaults to
"root".
Handle=
Configures the major number of unique
identifier of the qdisc, known as the handle. Takes a hexadecimal number in
the range 0x1–0xffff. Defaults to unset.
[QUICKFAIRQUEUEINGCLASS] SECTION OPTIONS
The [QuickFairQueueingClass] section manages the traffic control class of Quick Fair Queueing (qfq). Parent=Configures the parent Queueing Discipline
(qdisc). Takes one of "root", or a qdisc identifier. The qdisc
identifier is specified as the major and minor numbers in hexadecimal in the
range 0x1–Oxffff separated with a colon ("major:minor").
Defaults to "root".
ClassId=
Configures the unique identifier of the class.
It is specified as the major and minor numbers in hexadecimal in the range
0x1–Oxffff separated with a colon ("major:minor"). Defaults
to unset.
Weight=
Specifies the weight of the class. Takes an
integer in the range 1...1023. Defaults to unset in which case the kernel
default is used.
MaxPacketBytes=
Specifies the maximum packet size in bytes for
the class. When suffixed with K, M, or G, the specified size is parsed as
Kilobytes, Megabytes, or Gigabytes, respectively, to the base of 1024. When
unset, the kernel default is used.
[BRIDGEVLAN] SECTION OPTIONS
The [BridgeVLAN] section manages the VLAN ID configuration of a bridge port and accepts the following keys. Specify several [BridgeVLAN] sections to configure several VLAN entries. The VLANFiltering= option has to be enabled, see the [Bridge] section in systemd.netdev(5). VLAN=The VLAN ID allowed on the port. This can be
either a single ID or a range M-N. Takes an integer in the range
1...4094.
EgressUntagged=
The VLAN ID specified here will be used to
untag frames on egress. Configuring EgressUntagged= implicates the use
of VLAN= above and will enable the VLAN ID for ingress as well. This
can be either a single ID or a range M-N.
PVID=
The Port VLAN ID specified here is assigned to
all untagged frames at ingress. PVID= can be used only once.
Configuring PVID= implicates the use of VLAN= above and will
enable the VLAN ID for ingress as well.
EXAMPLES
Example 1. Static network configuration# /etc/systemd/network/50-static.network [Match] Name=enp2s0 [Network] Address=192.168.0.15/24 Gateway=192.168.0.1
# /etc/systemd/network/80-dhcp.network [Match] Name=en* [Network] DHCP=yes
# /etc/systemd/network/55-dhcpv6-pd-upstream.network [Match] Name=enp1s0 [Network] DHCP=ipv6 # The below setting is optional, to also assign an address in the delegated prefix # to the upstream interface. If not necessary, then comment out the line below and # the [DHCPPrefixDelegation] section. DHCPPrefixDelegation=yes # If the upstream network provides Router Advertisement with Managed bit set, # then comment out the line below and WithoutRA= setting in the [DHCPv6] section. IPv6AcceptRA=no [DHCPv6] WithoutRA=solicit [DHCPPrefixDelegation] UplinkInterface=:self SubnetId=0 Announce=no
# /etc/systemd/network/55-dhcpv6-pd-downstream.network [Match] Name=enp2s0 [Network] DHCPPrefixDelegation=yes IPv6SendRA=yes # It is expected that the host is acting as a router. So, usually it is not # necessary to receive Router Advertisement from other hosts in the downstream network. IPv6AcceptRA=no [DHCPPrefixDelegation] UplinkInterface=enp1s0 SubnetId=1 Announce=yes
# /etc/systemd/network/55-dhcpv4-6rd-upstream.network [Match] Name=enp1s0 [Network] DHCP=ipv4 # When DHCPv4-6RD is used, the upstream network does not support IPv6. # Hence, it is not necessary to wait for Router Advertisement, which is enabled by default. IPv6AcceptRA=no [DHCPv4] Use6RD=yes
# /etc/systemd/network/55-dhcpv4-6rd-downstream.network [Match] Name=enp2s0 [Network] DHCPPrefixDelegation=yes IPv6SendRA=yes # It is expected that the host is acting as a router. So, usually it is not # necessary to receive Router Advertisement from other hosts in the downstream network. IPv6AcceptRA=no [DHCPPrefixDelegation] UplinkInterface=enp1s0 SubnetId=1 Announce=yes
# /etc/systemd/network/25-bridge-static.netdev [NetDev] Name=bridge0 Kind=bridge
# /etc/systemd/network/25-bridge-static.network [Match] Name=bridge0 [Network] Address=192.168.0.15/24 Gateway=192.168.0.1 DNS=192.168.0.1
# /etc/systemd/network/25-bridge-slave-interface-1.network [Match] Name=enp2s0 [Network] Bridge=bridge0
# /etc/systemd/network/25-bridge-slave-interface-2.network [Match] Name=wlp3s0 [Network] Bridge=bridge0
# /etc/systemd/network/25-bridge-slave-interface-1.network [Match] Name=enp2s0 [Network] Bridge=bridge0 [BridgeVLAN] VLAN=1-32 PVID=42 EgressUntagged=42 [BridgeVLAN] VLAN=100-200 [BridgeVLAN] EgressUntagged=300-400
/etc/systemd/network/25-tunnels.network [Match] Name=ens1 [Network] Tunnel=ipip-tun Tunnel=sit-tun Tunnel=gre-tun Tunnel=vti-tun
/etc/systemd/network/25-tunnel-ipip.netdev [NetDev] Name=ipip-tun Kind=ipip
/etc/systemd/network/25-tunnel-sit.netdev [NetDev] Name=sit-tun Kind=sit
/etc/systemd/network/25-tunnel-gre.netdev [NetDev] Name=gre-tun Kind=gre
/etc/systemd/network/25-tunnel-vti.netdev [NetDev] Name=vti-tun Kind=vti
# /etc/systemd/network/30-bond1.network [Match] Name=bond1 [Network] DHCP=ipv6
# /etc/systemd/network/30-bond1.netdev [NetDev] Name=bond1 Kind=bond
# /etc/systemd/network/30-bond1-dev1.network [Match] MACAddress=52:54:00:e9:64:41 [Network] Bond=bond1
# /etc/systemd/network/30-bond1-dev2.network [Match] MACAddress=52:54:00:e9:64:42 [Network] Bond=bond1
# /etc/systemd/network/25-vrf.network [Match] Name=bond1 [Network] VRF=vrf1
# /lib/systemd/network/25-macvtap.network [Match] Name=enp0s25 [Network] MACVTAP=macvtap-test
# /etc/systemd/network/27-xfrm.netdev [NetDev] Name=xfrm0 Kind=xfrm [Xfrm] InterfaceId=7
# /etc/systemd/network/27-eth0.network [Match] Name=eth0 [Network] Xfrm=xfrm0
SEE ALSO
systemd(1), systemd-networkd.service(8), systemd.link(5), systemd.netdev(5), systemd-network-generator.service(8), systemd-resolved.service(8)NOTES
- 1.
- System and Service Credentials
- 2.
- Link-Local Multicast Name Resolution
- 3.
- Multicast DNS
- 4.
- DNS-over-TLS
- 5.
- DNSSEC
- 6.
- IEEE 802.1AB-2016
- 7.
- IP Sysctl
- 8.
- RFC 4941
- 9.
- RFC 1027
- 10.
- RFC 6275
- 11.
- RFC 5227
- 12.
- RFC 4862
- 13.
- RFC 3041
- 14.
- NetLabel
- 15.
- Linux Security Modules (LSMs)
- 16.
- NetLabel Fallback Peer Labeling
- 17.
- RFC 3484
- 18.
- RFC 4191
- 19.
- RFC 8520
- 20.
- RFC 7844
- 21.
- C-style escapes
- 22.
- RFC 5969
- 23.
- RFC 3315
- 24.
- RFC 8415
- 25.
- RFC 4291
- 26.
- RFC 7217
- 27.
- RFC 2131
- 28.
- RFC 2132
- 29.
- RFC 1542
- 30.
- RFC 4861
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