Here is the scenario: dropping excactly every other ping from default gateway to L3 directly connected server, but there is a switch between the server and the router. All Cisco devicse are hybrid 6500's. No load balancing or Ether Channel is configured in any switches or routers, or on the dual-threaded servers. Servers have redundant links to two switch with PFC's, to two with MSFC's running HSRP between them. The topology could best be described as a box. I have determined that the server's default gateway is pointed to the wrong vlan for the HSRP Virtual IP and have directed to reconfigure this to the appropriate Virtual IP for their Vlan.
The question is that I am attempting to explain the exact symmetery to the packet loss that I am experinencing with the incorrect default gateway on the servers. Seems to me that the server would not require a default gateway to return my ICMP requests, given that we are on the same subnet, and would return all pings. Anybody got a feasible explanation?
The other explanation for this symptom would be a switch port configured as an etherchannel that should not be. The switch is load balancing the traffic out a pair of ports, but only one is actually connected to the correct server.