DisplayFilters

DisplayFilters

Wireshark uses display filters for general packet filtering while viewing and for its ColoringRules.

The basics and the syntax of the display filters are described in the User's Guide.

The master list of display filter protocol fields can be found in the display filter reference.

If you need a display filter for a specific protocol, have a look for it at the ProtocolReference.

Display filter is not a capture filter

Capture filters (like tcp port 80) are not to be confused with display filters (like tcp.port == 80).
See also CaptureFilters: Capture filter is not a display filter.

Examples

Show only SMTP (port 25) and ICMP traffic:

 tcp.port eq 25 or icmp

Show only traffic in the LAN (192.168.x.x), between workstations and servers -- no Internet:

ip.src==192.168.0.0/16 and ip.dst==192.168.0.0/16

TCP buffer full -- Source is instructing Destination to stop sending data

 tcp.window_size == 0 && tcp.flags.reset != 1

Filter on Windows -- Filter out noise, while watching Windows Client - DC exchanges

 smb || nbns || dcerpc || nbss || dns

Sasser worm: --What sasser really did--

  ls_ads.opnum==0x09

Match packets containing the (arbitrary) 3-byte sequence 0x81, 0x60, 0x03 at the beginning of the UDP payload, skipping the 8-byte UDP header. Note that the values for the byte sequence implicitly are in hexadecimal only. (Useful for matching homegrown packet protocols.)

  udp[8:3]==81:60:03

The "slice" feature is also useful to filter on the vendor identifier part (OUI) of the MAC address, see the Ethernet page for details. Thus you may restrict the display to only packets from a specific device manufacturer. E.g. for DELL machines only:

  eth.addr[0:3]==00:06:5B

It is also possible to search for characters appearing anywhere in a field or protocol by using the contains operator.

Match packets that contains the 3-byte sequence 0x81, 0x60, 0x03 anywhere in the UDP header or payload:

  udp contains 81:60:03

Match packets where SIP To-header contains the string "a1762" anywhere in the header:

  sip.To contains "a1762"

The matches, or ~, operator makes it possible to search for text in string fields and byte sequences using a regular expression, using Perl regular expression syntax. Note: Wireshark needs to be built with libpcre in order to be able to use the matches operator.

Match HTTP requests where the last characters in the uri are the characters "gl=se":

  http.request.uri matches "gl=se$"

Note: The $ character is a PCRE punctuation character that matches the end of a string, in this case the end of http.request.uri field.

Filter by a protocol ( e.g. SIP ) and filter out unwanted IPs:

  ip.src != xxx.xxx.xxx.xxx && ip.dst != xxx.xxx.xxx.xxx && sip

With Wireshark 4.0+ you can select a specific a specific occurrence of a field. To use the layer operator, just put a number sign and a layer number after a field. For example, if we have a GRE packet with both outer and inner IPv4 layers,

ip.src#1 == 10.1.2.3

will match the outer address,

ip.src#2 == 10.1.2.3

will match the inner address, and

ip.src == 10.1.2.3

will match either address.

[ Feel free to contribute more ]

Gotchas

Some filter fields match against multiple protocol fields. For example, "ip.addr" matches against both the IP source and destination addresses in the IP header. The same is true for "tcp.port", "udp.port", "eth.addr", and others. It's important to note that

 ip.addr == 10.43.54.65

is equivalent to

 ip.src == 10.43.54.65 or ip.dst == 10.43.54.65

Before Wireshark 3.6, this can be counterintuitive in some cases. Suppose we want to filter out any traffic to or from 10.43.54.65. We might try the following:

 ip.addr != 10.43.54.65

which is equivalent to

 ip.src != 10.43.54.65 or ip.dst != 10.43.54.65

This translates to "pass all traffic except for traffic with a source IPv4 address of 10.43.54.65 and a destination IPv4 address of 10.43.54.65", which isn't what we wanted.

Instead we need to negate the expression, like so:

 ! ( ip.addr == 10.43.54.65 )

which is equivalent to

 ! (ip.src == 10.43.54.65 or ip.dst == 10.43.54.65)

This translates to "pass any traffic except with a source IPv4 address of 10.43.54.65 or a destination IPv4 address of 10.43.54.65", which is what we wanted.

This can also happen if, for example, you have tunneled protocols, so that you might have two separate IPv4 or IPv6 layers and two separate IPv4 or IPv6 headers, or if you have multiple instances of a field for other reasons, such as multiple IPv6 "next header" fields.

If you have a filter expression of the form name op value, where name is the name of a field, op is a comparison operator such as == or != or < or..., and value is a value against which you're comparing, it should be thought of as meaning "match a packet if there is at least one instance of the field named name whose value is (equal to, not equal to, less than, ...) value". The negation of that is "match a packet if there are no instances of the field named name whose value is (equal to, not equal to, less than, ...) value"; simply negating op, e.g. replacing == with != or < with >=, give you another "if there is at least one" check, which is not the negation of the original check.

With Wireshark 3.6+ the display filter syntax interpretation has been modified to prevent such easy mistakes. The original interpretation is still available, under a slightly different syntax. See the User's Guide for more information.

See Also

CaptureFilters

External Links

Imported from https://wiki.wireshark.org/DisplayFilters on 2020-08-11 23:13:34 UTC