Wireshark-users: Re: [Wireshark-users] Capturing and merging files from different machines
From: Jeff Morriss <[email protected]>
Date: Wed, 18 Jun 2008 11:44:45 -0400

Chris Swinney wrote:

I have taken a capture on two different machines from an in-line network tap (one to capture upstream, one to capture downstream data). I now need to merge these file, but when I ask Wireshark to merge them chronologically, it seems to merge them based on the initial time taken into the capture, not the actual capture time.
I have tried to mitigate time differences by synching both machines to 
an NTP server, but of course both captures are themselves started a 
different times. How can I best accomplish what I want? I’ve had a look 
at mergecap (as well as the inbuilt merge facility as shown above), but 
am not sure if this will still do what I’m after.
Maybe I'm being naive here but I would expect a "chronological merge" to 
merge the packets based on their (absolute) timestamps (that is, based 
on the time stamp of each packet--which is in secs+usecs since the 
epoch), not based on seconds since the beginning of the capture file.
(In fact I merge capture files quite frequently so I somewhat depend on 
this functionality.)

- what version of Wireshark are you using?
- what is your time display format (time of day, seconds since beginning of capture, etc.)? Not that it should matter, but...