Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
WIRESHARK-FILTER(4)	The Wireshark Network Analyzer	   WIRESHARK-FILTER(4)

NAME
       wireshark-filter	- Wireshark display filter syntax and reference

SYNOPSIS
       wireshark [other	options]
       [ -Y "display filter expression"	| b<--display-filter "display filter
       expression" ]>

       tshark [other options] [	-Y "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".

       Think of	a protocol or field in a filter	as implicitly having the
       "exists"	operator.

   Comparison operators
       Fields can also be compared against values.  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

   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 protocol or text 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 (quoted or unquoted), or bytes,
       expressed as a byte array, or for a single character, expressed as a
       C-style character constant.  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 (PCRE).  The "matches" operator is
       only implemented	for protocols and for protocol fields with a text
       string representation. Matches are case-insensitive by default.	For
       example,	to search for a	given WAP WSP User-Agent, you can write:

	   wsp.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.user_agent matches "(?-i)cldc"

       This is an example of PCRE'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 pcrepattern(3) man page at
       <https://perldoc.perl.org/perlre.html>).

   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

       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.

   Protocol field types
       Each protocol field is typed. The types are:

	   ASN.1 object	identifier
	   Boolean
	   Character string
	   Compiled Perl-Compatible Regular Expression (GRegex)	object
	   Date	and time
	   Ethernet or other MAC address
	   EUI64 address
	   Floating point (double-precision)
	   Floating point (single-precision)
	   Frame number
	   Globally Unique Identifier
	   IPv4	address
	   IPv6	address
	   IPX network number
	   Label
	   Protocol
	   Sequence of bytes
	   Signed integer, 1, 2, 3, 4, or 8 bytes
	   Time	offset
	   Unsigned integer, 1,	2, 3, 4, or 8 bytes
	   1-byte ASCII	character

       An integer may be expressed in decimal, octal, or hexadecimal notation,
       or as a C-style character constant.  The	following six display filters
       are equivalent:

	   frame.pkt_len > 10
	   frame.pkt_len > 012
	   frame.pkt_len > 0xa
	   frame.pkt_len > '\n'
	   frame.pkt_len > '\xa'
	   frame.pkt_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
       1 or any	other non-zero value, and "false" is expressed as zero.	 For
       example,	a token-ring packet's source route field is Boolean.  To find
       any source-routed packets, a display filter would be:

	   tr.sr == 1

       Non source-routed packets can be	found with:

	   tr.sr == 0

       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.dst eq www.mit.edu
	   ip.src == 192.168.1.1

       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 InterDomain 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 Class-B 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 Class
       C network as 'sneezy':

	   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).

       IPX networks are	represented by unsigned	32-bit integers.  Most likely
       you will	be using hexadecimal when testing IPX network values:

	   ipx.src.net == 0xc0a82c00

       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".

   The slice operator
       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:

	   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

       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

       A slice is always compared against either a string or a byte sequence.
       As a special case, when the slice is only 1 byte	wide, you can compare
       it against a hex	integer	that 0xff or less (which means it fits inside
       one byte). This is not allowed for byte sequences 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 numbers,
       since they would	be confused with hex numbers that are already allowed
       as byte strings.	Nevertheless, single-byte hex integers can be
       convenient:

	   frame[4] == 0xff

       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 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}

   Type	conversions
       If a field is a text string or a	byte array, it can be expressed	in
       whichever way is	most convenient.

       So, for instance, the following filters are equivalent:

	   http.request.method == "GET"
	   http.request.method == 47.45.54

       A range can also	be expressed in	either way:

	   frame[60:2] gt 50.51
	   frame[60:2] gt "PQ"

   Bit field operations
       It is also possible to define tests with	bit field operations.
       Currently the following bit field operation is supported:

	   bitwise_and,	&      Bitwise AND

       The bitwise AND operation allows	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.

       Similarly, filtering for	all WSP	GET and	extended GET methods is
       achieved	with:

	   wsp.pdu_type	& 0x40

       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

   Logical expressions
       Tests can be combined using logical expressions.	 These too are
       expressible in C-like syntax or with English-like abbreviations:

	   and,	&&   Logical AND
	   or,	||   Logical OR
	   not,	!    Logical NOT

       Expressions can be grouped by parentheses as well.  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 (llc
       exists)", 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.

       A special caveat	must be	given regarding	fields that occur more than
       once per	packet.	 "ip.addr" occurs twice	per IP packet, once for	the
       source address, and once	for the	destination address.  Likewise,
       "tr.rif.ring" fields can	occur more than	once per packet.  The
       following two expressions are not equivalent:

	       ip.addr ne 192.168.4.1
	   not ip.addr eq 192.168.4.1

       The first filter	says "show me packets where an ip.addr exists that
       does not	equal 192.168.4.1".  That is, as long as one ip.addr in	the
       packet does not equal 192.168.4.1, the packet passes the	display
       filter.	The other ip.addr could	equal 192.168.4.1 and the packet would
       still be	displayed.  The	second filter says "don't show me any packets
       that have an ip.addr field equal	to 192.168.4.1".  If one ip.addr is
       192.168.4.1, the	packet does not	pass.  If neither ip.addr field	is
       192.168.4.1, then the packet is displayed.

       It is easy to think of the 'ne' and 'eq'	operators as having an
       implicit	"exists" modifier when dealing with multiply-recurring fields.
       "ip.addr	ne 192.168.4.1"	can be thought of as "there exists an ip.addr
       that does not equal 192.168.4.1".  "not ip.addr eq 192.168.4.1" can be
       thought of as "there does not exist an ip.addr equal to 192.168.4.1".

       Be careful with multiply-recurring fields; they can be confusing.

       Care must also 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. Filtering with "ip.dst" selects only those IP
       packets that satisfy the	rule. Any other	packets, 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 or ip.dst ne 224.1.2.3
	   not ip.addr eq 224.1.2.3

       The first filter	uses "not ip" 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 has already been explained	above where filtering with
       multiply	occurring fields was discussed.

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:

       o   The online Display Filter Reference:
	   <https://www.wireshark.org/docs/dfref/>

       o   Help:Supported Protocols in Wireshark

       o   "tshark -G fields" on the command line

       o   The Wireshark wiki:
	   <https://gitlab.com/wireshark/wireshark/-/wikis/DisplayFilters>

NOTES
       The wireshark-filters 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 GRegex in
       GLib.  See
       <https://developer.gnome.org/glib/2.32/glib-regex-syntax.html> or
       <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.

3.4.6				  2021-06-02		   WIRESHARK-FILTER(4)

NAME | SYNOPSIS | DESCRIPTION | FILTER SYNTAX | FILTER FIELD REFERENCE | NOTES | SEE ALSO | AUTHORS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=wireshark-filter&sektion=4&manpath=FreeBSD+13.0-RELEASE+and+Ports>

home | help