Provided by: wireshark-common_4.2.6-1_amd64 
NAME
wireshark-filter - Wireshark display filter syntax and reference
SYNOPSIS
wireshark [other options] [ -Y "display filter expression" | --display-filter "display
filter expression" ]
tshark [other options] [ -Y "display filter expression" | --display-filter "display filter
expression" ]
DESCRIPTION
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/.
FILTER SYNTAX
Check whether a field or protocol exists
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.
Values and operators
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.
Comparison operators
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:
all tcp.port > 1024
any ip.addr != 1.1.1.1
The "any" and "all" modifiers take precedence over comparison operators such as "===" and
"any_eq".
Search and match operators
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.
Functions
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.
Protocol field types
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 (case-insensitive) or any non-zero
number. False is expressed as false (case-insensitive) 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):
ip.addr eq sneezy/24
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. The timezone can be given as "Z" or an
offset from UTC.
When not using ISO 8601 the timezone can be given as the strings "UTC", "GMT" or "UT" for
UTC or also given as an offset from UTC, plus some North American and Nautical/Military
designations (see the specification for %z in strptime(3)
<https://man.netbsd.org/strptime.3>). Note that arbitrary timezone names are not supported
however.
If the timezone is omitted then date and time values are interpreted as local time.
The slice operator
You can take a slice of a field if the field base type is a text string or a byte array
(the base type of most network address fields is bytes). For example, you can filter on
the vendor portion of an ethernet address (the first three bytes) like this:
eth.src[0:3] == 00:00:83
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
Slice indexes are zero-based. 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:
frame[-4:4] == 0.1.2.3
or
frame[-4:] == 0.1.2.3
As mentioned above the slice operator can be used on string and byte fields and will
respectively produce string or byte slices. String slices are indexed on UTF-8 codepoint
boundaries (i.e: internationalized characters), so the following comparison is true:
"touché"[5] == "é"
The example above generates an error because the compiler rejects constant expressions but
is otherwise syntactically correct and exemplifies the behaviour of string slices.
To obtain a byte slice of the same string the raw (@) operator can be used:
@"touché"[5-6] == c3:a9
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.
The layer operator
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:
tcp.port#[2-4]
means layers number 2, 3 or 4 inclusive. The hash symbol is required to distinguish a
layer range from a slice.
The at operator
By prefixing the field name with an at sign (@) the comparison is done against the raw
packet data for the field.
A character string must be decoded from a source encoding during dissection. If there are
decoding errors the resulting string will usually contain replacement characters:
browser.comment == "string is ����"
The at operator allows testing the raw undecoded data:
@browser.comment == 73:74:72:69:6e:67:20:69:73:20:aa:aa:aa:aa
The syntactical rules for a bytes field type apply to the second example.
The membership operator
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}
Implicit type conversions
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
Bitwise operators
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:
tcp.flags & 0x02
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:
eth.addr[0] & 0x0f == 2
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:
ip[42:2] & 40:ff
Arithmetic operators
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".
Protocol field references
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.
Logical expressions
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)
xor, ^^ Logical XOR (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.
Because each comparison has an implicit exists test for field values 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:
ip.dst ne 224.1.2.3
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
existence test and so is a shorter way to write the first.
FILTER FIELD REFERENCE
The entire list of display filters is too large to list here. You can can find references
and examples at the following locations:
• The online Display Filter Reference: https://www.wireshark.org/docs/dfref/
• View:Internals:Supported Protocols in Wireshark
• tshark -G fields on the command line
• The Wireshark wiki: https://gitlab.com/wireshark/wireshark/-/wikis/DisplayFilters
NOTES
The wireshark-filter(4) 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
SEE ALSO
wireshark(1), tshark(1), editcap(1), pcap(3), pcap-filter(7) or tcpdump(8) if it doesn’t
exist.
AUTHORS
See the list of authors in the Wireshark man page for a list of authors of that code.
2024-07-11 WIRESHARK-FILTER(4)