Re: Drifting timestamps

[Martin Roesch <roesch () sourcefire com>]

Hi Jake,

That'd have to be the system clock on the sensor drifting, the 
timestamps that Snort uses is based on a call to gettimeofday() that 
libpcap performs when it receives a new packet.  Snort has no internal 
time tracking mechanisms and in fact we take advantage of the fact that 
libpcap gives us time data "for free" to track time inside Snort.

      -Marty


On Oct 15, 2004, at 6:50 PM, Jacob Roberts wrote:

> We have a snort setup with barnyard which dumps in to a MySQL database.
> We stop snort and barnyard each day, delete the database, re-create it,
> then restart snort and barnyard.
>
> As snort runs through the day we start to see the timestamps of alerts
> drift behind actual time.  We aren't receiving an excessive amount of
> alerts so we ruled out Barnyard not being able to keep up with the
> alerts generated by Snort (I don't know if that would happen anyways)
>
> Has anyone had anything like this happen?  We haven't been able to 
> track
> it down and aren't sure what to do.
>
> Thanks,
> Jake Roberts
> Brigham Young University
> jake_roberts () byu edu
>
>
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--
Martin Roesch - Founder/CTO, Sourcefire Inc. - +1-410-290-1616
Sourcefire - Discover.  Determine.  Defend.
roesch () sourcefire com - http://www.sourcefire.com
Snort: Open Source Network IDS - http://www.snort.org



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