I'm working on setting up a backup link for our ASA 5505 and I've followed these directions:
http://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_configuration_example09186a00806e880b.shtml
The backup ISP gives us a dynamic address, however, when I enable the backup ISP's interface on the ASA, my vpn tunnels drop. As soon as I disable the backup interface, the tunnels come back up. I'm attempting to configure this across one of these tunnels, so obviously this is an issue, as is the fact that other people need the tunnels as well. I'm not sure what I did to make this happen, but I've been over the config many times and can't see anything different from the instructions in the link above.
I thought it might be trying to route traffic across the backup interface, but my primary interface is tracked and has SLA running on it, so I would assume it wouldn't roll over onto the backup interface.
Any help would be appreciated.