Wireshark mailing list archives
Re: Wireshark Capture Filter Using Offset
From: Sake Blok <sake () euronet nl>
Date: Tue, 20 Jul 2010 17:18:21 +0200
On 20 jul 2010, at 16:55, George E Burns wrote:
You mentioned the UDP header was 16 bytes, but I thought it was only 8 bytes. I have tried the recommended filter: udp port domain and (udp[19] & 0x78) = 0x28 , but that does not seem to trigger the capture. I ran a comparison trace without the filter and verified the target packets were being received by the analyzer. Any ideas?
Indeed the UDP header is 8 bytes long, so that would make the filter: udp port domain and (udp[11] & 0x78) = 0x28 More information about capture filters can be found at the links Joke has sent earlier in this thread: http://wiki.wireshark.org/CaptureFilters http://procana.homeunix.com/#BON And of course the tcpdump manual page is a great source. Hope this helps, Cheers, Sake PS If you really want to dig into it, tcpdump -d <filter> will show you what the compiled BPF code will be, which you can use to verify the filter (if you understand the produced "machine-code"). ___________________________________________________________________________ Sent via: Wireshark-users mailing list <wireshark-users () wireshark org> Archives: http://www.wireshark.org/lists/wireshark-users Unsubscribe: https://wireshark.org/mailman/options/wireshark-users mailto:wireshark-users-request () wireshark org?subject=unsubscribe
Current thread:
- Wireshark Capture Filter Using Offset George E Burns (Jul 19)
- Re: Wireshark Capture Filter Using Offset j.snelders (Jul 19)
- Re: Wireshark Capture Filter Using Offset Guy Harris (Jul 19)
- Re: Wireshark Capture Filter Using Offset Guy Harris (Jul 19)
- Re: Wireshark Capture Filter Using Offset Guy Harris (Jul 19)
- Re: Wireshark Capture Filter Using Offset George E Burns (Jul 20)
- Re: Wireshark Capture Filter Using Offset Sake Blok (Jul 20)
- Re: Wireshark Capture Filter Using Offset Guy Harris (Jul 20)
- Re: Wireshark Capture Filter Using Offset Guy Harris (Jul 19)
- Re: Wireshark Capture Filter Using Offset George E Burns (Jul 20)
- Re: Wireshark Capture Filter Using Offset Guy Harris (Jul 20)
- Re: Wireshark Capture Filter Using Offset j.snelders (Jul 19)