Wireshark (1), shark(1), edit cap(1), cap(3), cap- filter (7) or pump(8) if it doesn't exist. (Source: Filtering with “IP.DST” selects only those IP packets that satisfy the rule. It is easy to think of the 'né' and 'EQ' operators as having an implicit “exists” modifier when dealing with multiply-recurring fields. Similarly, filtering for all WSP GET and extended GET methods is achieved with: Remember that whenever a protocol or field name occurs in an expression, the “exists” operator is implicitly called.Ī special caveat must be given regarding fields that occur more than once per packet. The bitwise AND operation allows testing to see if one or more bits are set. If a field is a text string or a byte array, it can be expressed in whichever way is most convenient. A field may be checked for matches against a set of values simply with the membership operator. The “frame” protocol can be useful, encompassing all the data captured by Wireshark or Shark. IPv4 addresses can be represented in either dotted decimal notation or by using the hostname: IPv4 addresses can be compared with the same logical relations as numbers: EQ, né, gt, GE, Lt, and LE.ĬDR notation can also be used with hostnames, as in this example of finding IP addresses on the same Class C network as 'sneeze': The CDR notation can only be used on IP addresses or hostnames, not in variable names. For example, a token-ring packet's source route field is Boolean. Integer fields are converted to their decimal representation.Īn integer may be expressed in decimal, octal, or hexadecimal notation, or as a C-style character constant. Upper() and lower() are useful for performing case-insensitive string comparisons. The “matches” or “~” operator allows a filter to apply to a specified Perl-compatible regular expression (Pure).

The “contains” operator cannot be used on atomic fields, such as numbers or IP addresses. Think of a protocol or field in a filter as implicitly having the “exists” operator. If i find something interesting i always go back to the tcp stream concerning to see what follows what exactly.The simplest filter allows you to check for the existence of a protocol or field. View>TimeDisplayFormat>SecondsSincePreviousDisplayedPacket, then doubleclick on Time Column and go back up and see the packets that took the longest (be aware that this depends on your filter (eg filter on smb and this TimeFormat means that large time difference you see is the time that passed since the last packet that matched your smb filter was seen!). Maybe you’ve already used the time sort column to find the same answer?

Now you can hop from marked packet to marked packet by using “ctrl+shift+N” to see what leads up to this command, or go and look inside of the packets and find out why a command is used.

“smb.cmd=50” Before you are all smb commands wich took the longest to complete, now mark ‘m all by ctrl+shift+M, then clear. Here you can find wich command gives the largest delay’s, sort the rows, then right click and “prepare a filter”, use the filter (and save it for a rainy day), f.i. With this filter you can then go and have a look at all the SMB service response Time statistics that matter for your conversation, by going: “statistics>service response time> SMB” rightclick on a packet in the right stream and go “follow tcp stream” If SMB 1, then look at the general flow of the conversation, by filtering on: a. The last dialect listed, NT LM 0.12, is SMB 1.0.Īnd after see what client and server have agreed upon, find the response to this request (eg “Negotiate Protocol Response (0x72)”) In short you can tell by only looking if the agreed upon value is SMB 1.0 by filtering on “ = 5” You can go and start troubleshooting SMB in several way’s but there’s a lot of dark corners in that protocol! Here’s what i do first: 1.check if SMB version 1 is used (in SMB 2.1, loads of things have changed): You can find these values in the SMB negotiation part of an SMB conversation, right after the TCP 3-way handshake, use “smb.cmd = 0x72” which means filter on all “SMB Command: Negotiate Protocol (0x72)” to see what dialects the client is capable of.

Wireshark http syntax