Recently I had an issue with my 4006 switch. The switch has 5 line cards and a few ports in three of the modules lost layer 3 access. I mean to say, the ports were learning the mac adress but the users connected to those ports were not able to access their applicaions.
Soft resetting the modules one by one did not help the issue so I had to hard reboot the entire switch to fix the same.
I could not see any IOS bug causing this trouble.
I am curious enogh to know the reason why this happened( the possible reason) and what can be done as precaution to avoid such circumstances in future ...
Please do help...