Wireshark-users: Re: [Wireshark-users] question about fancy DHCP display filtering

From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Tue, 15 May 2007 09:51:20 -0700
Stefan Puiu wrote:

Is it possible (with this wireshark version) to specify a filter along the lines of "all packets that carry option x with value y"? As far as I can tell, all I can currently specify is "one packet that has one option type x and one option with value y", but not the same.

Unfortunately, not in general - the BOOTP/DHCP dissector doesn't have separate named fields for the values of all options it knows about.

Example filters I would need: - all DHCPDISCOVER packets that carry option 55 (parameter request list) with a certain value in the respective option (e.g. 1,3,58,59 being the sequence of values)

Unfortunately, there isn't a named field for the value of option 55, so you can't filter on that.

- all DHCPOFFER/DHCPACK packets without option 3

Similarly, there isn't a named field for the value of option 53, so you can't filter on the DHCP message type.

This should probably be fixed.