IPSEC VPN Tunnel and Multiple WAN Interfaces

[civic00typer]

I have a Cisco 1800 router with a T1 serial interface and another interface setup with a cable modem. I have setup the cable modem interface as the backup and the T1 as the primary. I am using an SLA to rollover to backup interface in case of failure of the primary. I also setup a route map to forward web traffic out the cable modem interface and all other traffic through the primary. Now I have a couple of remote sites that I want to establish IPSEC tunnels between. I was able to connect to both interfaces and get the IPSEC tunnel up... however, when I establish a tunnel on the cable modem interface (the backup), I can't access the remote network (Cisco 1800). It shows that the conneciton is successful, but it doesn't work. I have applied the crypto map to both interfaces (probably wouldn't have gotten this far if I didn't). When I say doesn't work, I mean I can't ping the internal management IP address (the gateway to the remote network). Any suggestions? Would be ideal to have a couple IPSEC tunnels through the cable modem and then setup to failover to the T1... other, more mission critical tunnels, will be setup with the T1.