Graphing with MRTG something other than active leases?

[Jerimiah Cole]

On Fri, 2008-10-10 at 12:58 +0200, Leif Arne Neset wrote:
> Nomad skrev:
> > Is anybody else using MRTG to create graphs for ISC DHCP?  I have graphs for
> > the active and known leases but I've been asked to do the same for the
> > number of DHCPDISCOVER and other messages.  We've had several instances of
> > clients going nuts and flooding our servers with DHCPDISCOVER and we'd like
> > to keep track of this.
> > Any thoughts?  Suggestions?  Currently we're running v3.1.0 on a redhat
> > enterprise v4 server.
> > 
> 
> We are starting a small script from the MRTG server that uses tcpdump, 
> on the dhcp servers, for 10 sec. to count the number of incoming dhcp 
> packets and returns a value to MRTG.

That will only capture a small snapshot of traffic, and ignores
potential peaks across the entire interval that MRTG is averaging
against (usually 5 minutes).  Why not just:

grep DISCOVER /var/log/dhcp.log | wc -l

I think MRTG is smart enough to realize when the log rotates and the
count plummets.

Jerimiah