RE: Drifting timestamps

["M. Shirk" <shirkdog_linux () hotmail com>]

In the default barnyard.conf, there is a setting to convert all timestamps 
to UTC

See the following:

# use localtime instead of UTC (*not* recommended because of timewarps)
#config localtime

This is the default for the configuration to use UTC. This might be it.

Shirkdog


> From: "Jacob Roberts" <jake_roberts () byu edu>
> To: "Martin Roesch" <roesch () sourcefire com>
> CC: <snort-users () lists sourceforge net>
> Subject: RE: [Snort-users] Drifting timestamps
> Date: Mon, 18 Oct 2004 13:18:27 -0600
>
> We check the timezones and clocks of all the systems involved.  They are
> all correct and don't drift from day to day.
>
> They daily routine is to Stop barnyard, stop snort, drop the Mysql
> database(not just deleted the records), re-create the database, start
> snort, start barnyard.
>
> At the time everything is restarted the timestamps are in sync with
> correct time.  As the system runs the timestamps drift
>
> We've narrowed it down to on of the following:
>         1. Something weird in Snort (probably not)
>         2. Something in Barnyard (we've no idea)
>         3. Something in Mysql. (We've added a timestamp column to the
> event table and it auto-inserted correct timestamps. So we don't thing
> its Mysql)
>
> Could this be a Barnyard thing?
>
> -----Original Message-----
> From: Martin Roesch [mailto:roesch () sourcefire com]
> Sent: Sunday, October 17, 2004 9:10 AM
> To: Jacob Roberts
> Cc: snort-users () lists sourceforge net
> Subject: Re: [Snort-users] Drifting timestamps
>
>
> 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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