NAME
ipfw — IP packet filter and traffic accountingSYNOPSIS
To compile the driver into the kernel, place the following option in the kernel configuration file:options
IPFIREWALL
Other related kernel options which may also be useful are:
options
IPFIREWALL_DEFAULT_TO_ACCEPT
options IPFIREWALL_VERBOSE
options IPFIREWALL_VERBOSE_LIMIT=100
To load the driver as a module at boot time, add the following line into the
loader.conf(5) file:
options IPFIREWALL_VERBOSE
options IPFIREWALL_VERBOSE_LIMIT=100
ipfw_load="YES"
DESCRIPTION
The ipfw system facility allows filtering, redirecting, and other operations on IP packets travelling through network interfaces. The default behavior of ipfw is to block all incoming and outgoing traffic. This behavior can be modified, to allow all traffic through the ipfw firewall by default, by enabling theIPFIREWALL_DEFAULT_TO_ACCEPT
kernel option. This option may be useful when configuring
ipfw for the first time. If the default
ipfw behavior is to allow everything, it is
easier to cope with firewall-tuning mistakes which may accidentally block all
traffic.
To enable logging of packets passing through ipfw,
enable the IPFIREWALL_VERBOSE kernel
option. The IPFIREWALL_VERBOSE_LIMIT option
will prevent syslogd(8) from flooding system logs
or causing local Denial of Service. This option may be set to the number of
packets which will be logged on a per-entry basis before the entry is
rate-limited.
The user interface for ipfw is implemented by the
ipfw(8) utility, so please refer to the
ipfw(8) manpage for a complete description of the
ipfw capabilities and how to use it.
SEE ALSO
setsockopt(2), divert(4), ip(4), ipfw(8), sysctl(8), syslogd(8), pfil(9)| October 25, 2012 | Debian |