I suddenly lost communication between server and cat 6509 (catos) switch.
Nothing on the switch indicated failure.
I ran show port 9/13 and it showed as connected. Interface on the server was up. I could see TX number on a switch going up but not RX. What is even more weird is when I ran tcpdump on the server, i saw CDP info going to the server, but notghing else. Usually i see other stuff like spanning tree messages or HSRP.
I then plugged in the server to the other switch port using the same GBIC, the same cable and it worked. So it had to be port on a switch that failed. Any ideas why the port did not show as down?
How can i further troubleshoot what went wrong?