Re: [tcpdump-workers] tcpdump and timestamps

2010-11-09 Thread Richard Huddleston
There are two simple cases to rule out: 1. The capture was taken using a Napatech or Endace card, which uses its own clock which may or may not be in sync with the host clock. 2. There's an unexpected local timezone on the machine used to read and display the packet capture. Is your client

Re: [tcpdump-workers] tcpdump and timestamps

2010-11-09 Thread Andrej van der Zee
Hi Gary, Thank you for your clear reply, as always. > > WinDump, the Windows port of tcpdump, uses WinPcap, the Windows port of > libpcap.  The time stamps come from the WinPcap driver, which might, > depending on how it's configured, read the system clock for each packet, or > might read it w

Re: [tcpdump-workers] tcpdump and timestamps

2010-11-09 Thread Guy Harris
On Nov 9, 2010, at 1:15 AM, Andrej van der Zee wrote: > Today I received a tcpdump file from a client with timestamps that did > not correspond to the system clock. If I remember correctly, tcpdump > does not store complete timestamps but only a delta compared to the > first timestamp. No. Each

[tcpdump-workers] tcpdump and timestamps

2010-11-09 Thread Andrej van der Zee
Hi, Today I received a tcpdump file from a client with timestamps that did not correspond to the system clock. If I remember correctly, tcpdump does not store complete timestamps but only a delta compared to the first timestamp. I guess tcpdump does not read the system clock every time, but has it