wireshark-filter - Wireshark display filter syntax and reference
wireshark [other options] [
-Y "display filter
expression" |
--display-filter "display filter
expression" ]
tshark [other options] [
-Y "display filter expression"
|
--display-filter "display filter expression" ]
Wireshark and
TShark share a powerful filter engine that helps
remove the noise from a packet trace and lets you see only the packets that
interest you. If a packet meets the requirements expressed in your filter,
then it is displayed in the list of packets. Display filters let you compare
the fields within a protocol against a specific value, compare fields against
fields, and check the existence of specified fields or protocols.
Filters are also used by other features such as statistics generation and packet
list colorization (the latter is only available to
Wireshark). This
manual page describes their syntax. A comprehensive reference of filter fields
can be found within Wireshark and in the display filter reference at
<
https://www.wireshark.org/docs/dfref/>.
The simplest filter allows you to check for the existence of a protocol or
field. If you want to see all packets which contain the IP protocol, the
filter would be "ip" (without the quotation marks). To see all
packets that contain a Token-Ring RIF field, use "tr.rif".
Whenever a protocol or field appears as the argument of a function in a filter,
an exists operator for that protocol or field implicitly appears.
Each field has a value, and that value can be used in operations with comparable
values (which may be literals, other fields, or function results). The value
of a field is not necessarily what appears in the
Wireshark display or
TShark output. For example, a protocol is semantically equivalent to
the sequence of bytes that it spans, not its displayed text in the protocol
tree.
The comparison operators can be expressed either through English-like
abbreviations or through C-like symbols:
eq, == Equal
ne, != Not Equal
gt, > Greater Than
lt, < Less Than
ge, >= Greater than or Equal to
le, <= Less than or Equal to
The ordering depends on the value type in the usual way (e.g., lexicographic for
strings and arithmetic for integers.) A field may appear more than once in a
given frame. In that case equality can be strict (all fields must match the
condition) or not (any field must match the condition). The inequality is the
logical negation of equality. The following table contains all equality
operators, their aliases and meaning:
eq, any_eq, == Any field must be equal
ne, all_ne, != All fields must be not equal
all_eq, === All fields must be equal
any_ne, !== Any fields must be not equal
The operators "any" or "all" can be used with any comparison
operator to make the test match any or all fields:
The "any" and "all" modifiers take precedence over
comparison operators such as "===" and "any_eq".
Additional operators exist expressed only in English, not C-like syntax:
contains Does the protocol, field or slice contain a value
matches, ~ Does the string match the given case-insensitive
Perl-compatible regular expression
The "contains" operator allows a filter to search for a sequence of
characters, expressed as a string, or bytes, expressed as a byte array. The
type of the left hand side of the "contains" operator must be
comparable to that of the right hand side after any implicit or explicit
conversions.
For example, to search for a given HTTP URL in a capture, the following filter
can be used:
http contains "https://www.wireshark.org"
The "contains" operator cannot be used on atomic fields, such as
numbers or IP addresses.
The "matches" or "~" operator allows a filter to apply to a
specified Perl-compatible regular expression (PCRE2). The regular expression
must be a double quoted string. The left hand side of the "matches"
operator must be a string, which can be a non-stringlike field implicitly or
explicitly converted to a string. Matches are case-insensitive by default. For
example, to search for a given WAP WSP User-Agent, you can write:
wsp.header.user_agent matches "cldc"
This would match "cldc", "CLDC", "cLdC" or any
other combination of upper and lower case letters.
You can force case sensitivity using
wsp.header.user_agent matches "(?-i)cldc"
This is an example of PCRE2’s
(?option
) construct.
(?-i) performs a case-sensitive pattern match but other options can be
specified as well. More information can be found in the
pcre2pattern(3)|
https://www.pcre.org/current/doc/html/pcre2pattern.html man
page.
The filter language has the following functions:
upper(string-field) - converts a string field to uppercase
lower(string-field) - converts a string field to lowercase
len(field) - returns the byte length of a string or bytes field
count(field) - returns the number of field occurrences in a frame
string(field) - converts a non-string field to string
max(f1,...,fn) - return the maximum value
min(f1,...,fn) - return the minimum value
abs(field) - return the absolute value of numeric fields
upper() and lower() are useful for performing case-insensitive string
comparisons. For example:
upper(ncp.nds_stream_name) contains "MACRO"
lower(mount.dump.hostname) == "angel"
string() converts a field value to a string, suitable for use with operators
like "matches" or "contains". Integer fields are converted
to their decimal representation. It can be used with IP/Ethernet addresses (as
well as others), but not with string or byte fields. For example:
string(frame.number) matches "[13579]$"
gives you all the odd packets.
max() and min() take any number of arguments and returns one value, respectively
the largest/smallest. The arguments must all have the same type.
Each protocol field is typed. The types are:
ASN.1 object identifier, plain or relative
AX.25 address
Boolean
Byte sequence
Character string
Character, 1 byte
Date and time
Ethernet or other MAC address
EUI64 address
Fibre Channel WWN
Floating point, single or double precision
Frame number
Globally Unique Identifier
IEEE-11073 floating point, 16 or 32 bits
IPv4 address
IPv6 address
IPX network number
Label
OSI System-ID
Protocol
Signed integer, 1, 2, 3, 4, or 8 bytes
Time offset
Unsigned integer, 1, 2, 3, 4, or 8 bytes
VINES address
An integer may be expressed in decimal, octal, hexadecimal or binary notation,
or as a C-style character constant. The following seven display filters are
equivalent:
frame.len > 10
frame.len > 012
frame.len > 0xa
frame.len > 0b1010
frame.len > '\n'
frame.len > '\x0a'
frame.len > '\012'
Boolean values are either true or false. In a display filter expression testing
the value of a Boolean field, true is expressed as the word "True"
or "TRUE" (without quotes) or any non-zero number. False is
expressed as "False" or "FALSE" or the number zero. For
example, a token-ring packet’s source route field is Boolean. To find
any source-routed packets, a display filter would be any of the following:
tr.sr == 1
tr.sr == True
tr.sr == TRUE
Non source-routed packets can be found with:
tr.sr == 0
tr.sr == False
tr.sr == FALSE
Ethernet addresses and byte arrays are represented by hex digits. The hex digits
may be separated by colons, periods, or hyphens:
eth.dst eq ff:ff:ff:ff:ff:ff
aim.data == 0.1.0.d
fddi.src == aa-aa-aa-aa-aa-aa
echo.data == 7a
IPv4 addresses can be represented in either dotted decimal notation or by using
the hostname:
ip.src == 192.168.1.1
ip.dst eq www.mit.edu
IPv4 addresses can be compared with the same logical relations as numbers: eq,
ne, gt, ge, lt, and le. The IPv4 address is stored in host order, so you do
not have to worry about the endianness of an IPv4 address when using it in a
display filter.
Classless Inter-Domain Routing (CIDR) notation can be used to test if an IPv4
address is in a certain subnet. For example, this display filter will find all
packets in the 129.111 network:
ip.addr == 129.111.0.0/16
Remember, the number after the slash represents the number of bits used to
represent the network. CIDR notation can also be used with hostnames, as in
this example of finding IP addresses on the same network as 'sneezy' (requires
that 'sneezy' resolve to an IP address for filter to be valid):
The CIDR notation can only be used on IP addresses or hostnames, not in variable
names. So, a display filter like "ip.src/24 == ip.dst/24" is not
valid (yet).
Transaction and other IDs are often represented by unsigned 16 or 32 bit
integers and formatted as a hexadecimal string with "0x" prefix:
(dhcp.id == 0xfe089c15) || (ip.id == 0x0373)
Strings are enclosed in double quotes:
http.request.method == "POST"
Inside double quotes, you may use a backslash to embed a double quote or an
arbitrary byte represented in either octal or hexadecimal.
browser.comment == "An embedded \" double-quote"
Use of hexadecimal to look for "HEAD":
http.request.method == "\x48EAD"
Use of octal to look for "HEAD":
http.request.method == "\110EAD"
This means that you must escape backslashes with backslashes inside double
quotes.
smb.path contains "\\\\SERVER\\SHARE"
looks for \\SERVER\SHARE in "smb.path". This may be more conveniently
written as
smb.path contains r"\\SERVER\SHARE"
String literals prefixed with 'r' are called "raw strings". Such
strings treat backslash as a literal character. Double quotes may still be
escaped with backslash but note that backslashes are always preserved in the
result.
The following table lists all escape sequences supported with strings and
character constants:
\' single quote
\" double quote
\\ backslash
\a audible bell
\b backspace
\f form feed
\n line feed
\r carriage return
\t horizontal tab
\v vertical tab
\NNN arbitrary octal value
\xNN arbitrary hexadecimal value
\uNNNN Unicode codepoint U+NNNN
\UNNNNNNNN Unicode codepoint U+NNNNNNNN
Date and time values can be given in ISO 8601 format or using a legacy
month-year-time format:
"2020-07-04T12:34:56"
"Sep 26, 2004 23:18:04.954975"
The 'T' separator in ISO 8601 can be omitted. ISO 8601 supports timezone
designators as UTC or an offset from UTC. Legacy formats can append the value
"UTC" at the end to specify time in Coordinated Universal Time.
Otherwise date and time values are interpreted as local time.
You can take a slice of a field if the field is a text string or a byte array.
For example, you can filter on the vendor portion of an ethernet address (the
first three bytes) like this:
Another example is:
http.content_type[0:4] == "text"
You can use the slice operator on a protocol name, too. The "frame"
protocol can be useful, encompassing all the data captured by
Wireshark
or
TShark.
token[0:5] ne 0.0.0.1.1
llc[0] eq aa
frame[100-199] contains "wireshark"
The following syntax governs slices:
[i:j] i = start_offset, j = length
[i-j] i = start_offset, j = end_offset, inclusive.
[i] i = start_offset, length = 1
[:j] start_offset = 0, length = j
[i:] start_offset = i, end_offset = end_of_field
Offsets can be negative, in which case they indicate the offset from the
end of the field. The last byte of the field is at offset -1, the last
but one byte is at offset -2, and so on. Here’s how to check the last
four bytes of a frame:
or
A slice can always be compared against either a string or a byte sequence.
Slices can be combined. You can concatenate them using the comma operator:
ftp[1,3-5,9:] == 01:03:04:05:09:0a:0b
This concatenates offset 1, offsets 3-5, and offset 9 to the end of the ftp
data.
A field can be restricted to a certain layer in the protocol stack using the
layer operator (#), followed by a decimal number:
ip.addr#2 == 192.168.30.40
matches only the inner (second) layer in the packet. Layers use simple stacking
semantics and protocol layers are counted sequentially starting from 1. For
example, in a packet that contains two IPv4 headers, the outer (first) source
address can be matched with "ip.src#1" and the inner (second) source
address can be matched with "ip.src#2".
For more complicated ranges the same syntax used with slices is valid:
means layers number 2, 3 or 4 inclusive. The hash symbol is required to
distinguish a layer range from a slice.
A field may be checked for matches against a set of values simply with the
membership operator. For instance, you may find traffic on common HTTP/HTTPS
ports with the following filter:
tcp.port in {80,443,8080}
as opposed to the more verbose:
tcp.port == 80 or tcp.port == 443 or tcp.port == 8080
To find HTTP requests using the HEAD or GET methods:
http.request.method in {"HEAD", "GET"}
The set of values can also contain ranges:
tcp.port in {443, 4430..4434}
ip.addr in {10.0.0.5 .. 10.0.0.9, 192.168.1.1..192.168.1.9}
frame.time_delta in {10 .. 10.5}
Fields which are sequences of bytes, including protocols, are implicitly
converted to strings for comparisons against (double quoted) literal strings
and raw strings.
So, for instance, the following filters are equivalent:
tcp.payload contains "GET"
tcp.payload contains 47.45.54
As noted above, a slice can also be compared in either way:
frame[60:2] gt 50.51
frame[60:2] gt "PQ"
The inverse does not occur; stringlike fields are not implicitly converted to
byte arrays. (Some operators allow stringlike fields to be compared with
unquoted literals, which are then treated as strings; this is deprecated in
general and specifically disallowed by the "matches" operator.
Literal strings should be double quoted for clarity.)
A hex integer that is 0xff or less (which means it fits inside one byte) can be
implicitly converted to a byte string. This is not allowed for hex integers
greater than one byte, because then one would need to specify the endianness
of the multi-byte integer. Also, this is not allowed for decimal or octal
numbers, since they would be confused with the hex numbers that make up byte
string literals. Nevertheless, single-byte hex integers can be convenient:
frame[4] == 0xff
frame[1:4] contains 0x02
It is also possible to define tests with bitwise operations. Currently the
following bitwise operator is supported:
bitwise_and, & Bitwise AND
The bitwise AND operation allows masking bits and testing to see if one or more
bits are set. Bitwise AND operates on integer protocol fields and slices.
When testing for TCP SYN packets, you can write:
That expression will match all packets that contain a "tcp.flags"
field with the 0x02 bit, i.e. the SYN bit, set.
To match locally administered unicast ethernet addresses you can use:
When using slices, the bit mask must be specified as a byte string, and it must
have the same number of bytes as the slice itself, as in:
Arithmetic expressions are supported with the usual operators:
+ Addition
- Subtraction
* Multiplication
/ Division
% Modulo (integer remainder)
For example it is possible to filter for UDP destination ports greater or equal
by one to the source port with the expression:
udp.dstport >= udp.srcport + 1
It is possible to group arithmetic expressions using curly brackets (parenthesis
will not work for this):
tcp.dstport >= 4 * {tcp.srcport + 3}
Do not confuse this usage of curly brackets with set membership.
An unfortunate quirk in the filter syntax is that the subtraction operator must
be preceded by a space character, so "A-B" must be written as
"A -B" or "A - B".
A variable using a sigil with the form ${some.proto.field} is called a field
reference. A field reference is a field value read from the currently selected
frame in the GUI. This is useful to build dynamic filters such as, frames
since the last five minutes to the selected frame:
frame.time_relative >= ${frame.time_relative} - 300
Field references share a similar notation to macros but are distinct syntactical
elements in the filter language.
Tests can be combined using logical expressions. These too are expressible in
C-like syntax or with English-like abbreviations. The following table lists
the logical operators from highest to lowest precedence:
not, ! Logical NOT (right-associative)
and, && Logical AND (left-associative)
or, || Logical OR (left-associative)
The evaluation is always performed left to right. Expressions can be grouped by
parentheses as well. The expression "A and B or not C or D and not E or
F" is read:
(A and B) or (not C) or (D and (not E)) or F
It’s usually better to be explicit about grouping using parenthesis. The
following are all valid display filter expressions:
tcp.port == 80 and ip.src == 192.168.2.1
not llc
http and frame[100-199] contains "wireshark"
(ipx.src.net == 0xbad && ipx.src.node == 0.0.0.0.0.1) || ip
Remember that whenever a protocol or field name occurs in an expression, the
"exists" operator is implicitly called. The "exists"
operator has the highest priority. This means that the first filter expression
must be read as "show me the packets for which tcp.port exists and equals
80, and ip.src exists and equals 192.168.2.1". The second filter
expression means "show me the packets where not exists llc", or in
other words "where llc does not exist" and hence will match all
packets that do not contain the llc protocol. The third filter expression
includes the constraint that offset 199 in the frame exists, in other words
the length of the frame is at least 200.
Each comparison has an implicit exists test for any field value. Care must be
taken when using the display filter to remove noise from the packet trace. If,
for example, you want to filter out all IP multicast packets to address
224.1.2.3, then using:
may be too restrictive. This is the same as writing:
ip.dst and ip.dst ne 224.1.2.3
The filter selects only frames that have the "ip.dst" field. Any other
frames, including all non-IP packets, will not be displayed. To display the
non-IP packets as well, you can use one of the following two expressions:
not ip.dst or ip.dst ne 224.1.2.3
not ip.dst eq 224.1.2.3
The first filter uses "not ip.dst" to include all non-IP packets and
then lets "ip.dst ne 224.1.2.3" filter out the unwanted IP packets.
The second filter also negates the implicit existance test and so is a shorter
way to write the first.
The entire list of display filters is too large to list here. You can can find
references and examples at the following locations:
•View:Internals:Supported
Protocols in Wireshark
•tshark -G fields on the command
line
The manpage is part of the
Wireshark
distribution. The latest version of
Wireshark can be found at
<
https://www.wireshark.org>.
Regular expressions in the "matches" operator are provided by the
PCRE2 library. See
<
https://www.pcre.org/> for more information.
This manpage does not describe the capture filter syntax, which is different.
See the manual page of
pcap-filter(7) or, if that doesn’t exist,
tcpdump(8), or, if that doesn’t exist,
<
https://gitlab.com/wireshark/wireshark/-/wikis/CaptureFilters> for a
description of capture filters.
Display Filters are also described in the User’s Guide:
<
https://www.wireshark.org/docs/wsug_html_chunked/ChWorkBuildDisplayFilterSection.html>
wireshark(1),
tshark(1),
editcap(1),
pcap(3),
pcap-filter(7) or
tcpdump(8) if it
doesn’t exist.
See the list of authors in the
Wireshark man page for a list of authors
of that code.