Posted by: Anonymous
on February 21, 2008 12:07 PM
I have something like this set up, with one little addition, i have a script running as a daemon, polling the remote gateways MAC every few seconds, if a gateway fails to answer 3 times, it will trigger a script that clear the dead route from the routing table and clear the routing cache for routes that goes through the faulty gateway. this works very well, and mostly nobody but me notice if a connection goes down. the script will add the route back to the routing table when the faulty gateway is restored. originally i had a setup just like the one described here, it works well if you dont have loadbalaning set up, but just use one route at the time. if you have loadbalancing you would need a script like mine to ensure true failover.
unlike BGP and other multigateway protocols, this method will of course loose connections when one gateway goes down, this cant be avoided unless you have control over both ends on the redundant network (your ISPs routers too).