Hosts segment A -> FWSM -> ROUTER1 -> WAN Link -> ROUTER2 -> Host segment B
Suddenly, I am not able to ping hosts B from hosts A. I can see sync timeouts on the FWSM but nothing shows on the debug ip packet detail on ROUTER1. I can ping the ethernet of ROUTER1 but not beyond that. All the ethernet and serials links are up. I don't see any drops on the router as well. Router ethernets have been configured with GLBP. Routes are not changed. Would could be the problem. No new access-list added. VLANs are correct. Where should I start.