[kwlug-disc] Multiple gateways on one subnet

john at netdirect.ca john at netdirect.ca
Tue May 26 10:50:22 EDT 2009

kwlug-disc-bounces at kwlug.org wrote on 05/25/2009 06:45:13 PM:
> Thanks. It's clearly going to take more work for me to understand
> this, but it is a good document. Even knowing thet the proper term is
> "multi-isp" is helpful. 
> Overall I think that IPCop is the wrong tool for this job. I think it
> does not even have iproute2, which many tutorials (including the
> Shorewall page) want me to use. In the interest of laziness and 
> I may chicken out and use DHCP reservations to solve the problem. 

I would think that one of the routing protocols might work. OSPF is what 
I've used in cases like this in the past. Linux supports OSPF using the 
Zebra package. It's not too hard to setup, like all things linux it takes 
a few hours to understand but only results in a few lines of actual 

You could also consider a manual approach. Choose a point to ping from 
each router. It could be the ISP's router or a common point like Google or 
OpenDNS. When a ping fails replace the default gateway with the remote 
IPCop's address. Sensing a recovery is a little tougher to do now that 
your gateway has changed.

Iproute2 can help you with this and is likely available as an add-on to 

John Van Ostrand
Net Direct Inc.
564 Weber St. N. Unit 12
Waterloo, ON N2L 5C6
john at netdirect.ca
Ph: 866-883-1172
Linux Solutions / IBM Hardware
Fx: 519-883-8533

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