[plug] Monitoring IP

[Matt Kemner]

On Thu, 4 Jan 2001, Earnshaw, Mike wrote:

> I am looking for a program that will allow me to monitor the IP traffic
> on a router in our network. The router is not connected directly to any
> machine but a port on the network itself.

> Something like tcpdump or MRTG I suppose.

MRTG would be your best bet, providing the router talks snmp (most do)
what brand router is it?

> As far as I
> see the crux is that the router is not piped through another machine.

Yeah, which rules out using ipchains as a counter (which adds flexibility)

> Any pointers from more knowledgeable persons please. Thanks

download & install (or apt-get if running Debian) mrtg, then run the
provided cfgmaker script with the parameters of community at host
where community is the snmp read community configured on the router
(defaults to public, and is STRONGLY suggested is changed if it is) and
host is the hostname or IP address of the router.

Pipe the output from cfgmaker to the end of the sample mrtg.conf provided,
and then modify to suit.  The file is fairly well commented and most
should be self explanatory, and in fact often the defaults are good.
WorkDir and MaxBytes are the main things you should change.

 - Matt