After upgrading software in my catalyst 6500 to version IOS 12.1(23)E3
i have found out that all servers using APA in Lan Monitor mode
failed. APA is unable to be established. Standby NIC use speciall
frames in L2 to periodically check if the second NIC (active) if it is
still working, and it seems that after upgrade such frames do not pass
the switch. They get into the switch for sure, because there are MAC
addresses of the NIC`s in mac-address table, but when I sniff traffic
on the trunk connecting 2 CATALYST`S I don`t see them.
I do not know if it is a problem with software or anything else. If
anybody meet the same problem please let my know how to fix it.
Thx in advance