Hi All

I have a community network in my apartment block where we all pitch in for two internet connections and then we all share them. I'm the admin for setting all this and am wondering if there is a way of switching between the two connections. Two ISP uplinks are of course running to a 3-nic'd Gentoo router.

Two balance the load under the two isp's I made this route
ip route add default scope global nexthop via (gateway1) dev eth0 weight 1 nexthop via (gateway2) dev eth1 weight 1

I have also, using iproute2, set up two tables, T1 and T2. T1 runs to ISP 1 and T2 runs to ISP 2, I'm using fwmark to make this happen.

IE:
ip rule add fwmark 1 table T1
ip rule add fwmark 2 table T2

So using an iptables command like
i can send all ssh traffic thru ISP 2. What I want to do is: If ISP 1 goes down then for the route to mark all packets with 2, or vice versa. Something to the effect of "if so many packets go answered in 'x' seconds then switch routes to this"

Now maybe I'm going about this wrong and ip and tc commands can't do this, but I don't know. Now I know that zebra has something called OSPF, open shortest path first, but I'm not quite sure if this will solve my problem. Plus can zebra and the ip command work in conjunction of each other.

anyone?

To do simple failover, OSPF is an appropriate solution, however, your ISP needs to be in the OSPF area with your router.

Per packet load balancing is most likely not possible at all on those circuits, but per flow (which fails over automatically) should be. However, once again, you need the ISP to do stuff on their end too, which I'm guessing is part of the problem?

I'm not sure if the ISP is the problem, I have two different ISP's. Now I don't know if the two seperate ISP's are in area with my router. Per packet load balancing is pretty crappy on my setup and generally wouldn't work unless I went round robin, but since one line is faster than the other this would slow me down more than anyything. Thats why I put the mark system in.

My basic question is that if I punch in all the stuff zebra needs into ospfd will it failover?

Ouch, I didn't realize they were 2 completely different ISP's. Round Robin per packet may not work for you anyways if either ISP does uRPF filtering (like they should) on their end. The only way I can think of (off the top of my head) to seamlessly do what you want, since you're multi-homed, is to get an AS number and run BGP... This will definitely require coordination with both ISP's!