Bandwidth usage monitoring on border router

Unanswered Question
Jul 1st, 2008

I have a 2811 acting as a border router (outside the firewall) at a remote site with two internet T1's (separate ISPs) terminating into it. I need to be able to monitor the bandwidth usage on one of the internet T1s to see if we are hitting peaks and need more room with new traffic we are generating.

I use a Netflow monitoring tool inside my WAN to monitor bandwidth on all my P2P T1s between the offices but the border router can't see my internal network outside the firewall.

Is there logging I can turn on in the router or a CLI command I can run natively to see this?

I have this problem too.
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zztopping Wed, 07/02/2008 - 07:14

Nothing native in the CLI(that I'm aware of). I would open a pinhole in your firewall and export the netflow data to your netflow app.

Or use the Solarwinds Engineering toolset's bandwidth monitor. Good lil suite of tools.

qbakies11 Wed, 07/02/2008 - 07:34

All of interfaces on the border router are external, real world IPs and it doesn't know that my internal network exists so how would I route the traffic to my internal LAN IP?

zztopping Wed, 07/02/2008 - 07:56

I'm assume your firewall is doing the NATing. Just configure portforwarding so that UDP 2055 packets sent to the public firewall IP are forwarded to your internal Netflow host.

This is not that secure, but its up to you if this would be considered acceptable risk or not. In my opinion, if its not a Bank or a Military contractor, then its fine ;-)


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