To ping or not to ping

[cbrowns]

I have a lab setup with a 2500 series router. I have one workstation connected to a 1900 catalyst switch. The ethernet interface on the router is also connected to the switch. The ethernet interface and the workstation are on the same subnet. The default gateway for the workstation is the ethernet interface. When I ping the workstation from the router (Hyperterminal) it does not work. When I ping the router from the workstation (command prompt) it does work. If I ping the router from the workstation and at the same time ping the workstation from the router then they both work. Any ideas?

[rfroom]

What is configured on the ethernet interface of the router? (ACLs, Firewall features, etc.)

[rfroom]

Make sure you disable any network port configuration on the cat1900.

[cbrowns]

No acl's on the router. No firewall either. No vlan on the cat1900. No netork port conf on the cat1900.

[Gilles Dufour]

check the cam entry on switch for the router mac address and the server mac address.

Maybe try to disable spanning tree and make the switch port to port-fast.

If the problem persist, use a sniffer to see if the router is sending an icmp echo and whether or not the server does reply.