[c-nsp] Weird LAN Problems

[John Neiberger]

We're having some really strange problems on our LAN today and I can't
figure it out. We have a 6513 running 12.2(18)SXF4, several Catatalyst
2900 series switches (running CatOS, of course) and a few 2950
switches running varying versions of code. There is an FWSM running
3.1(1) in the 6513.

There was a log message on the 6513 this morning that said that the
FWSM had been switched to non-transparent VTP mode. I thought that was
odd but didn't think much of it. A little while later, we noticed that
none of the ports on one 2950 seemed to be working any longer.
Everything looked fine from the switches perspective--VLAN database
was intact, ports were up, no error, nothing in the logs, trunking was
still up, VLANs were allowed on the trunk--yet the ports that weren't
in the native VLAN seemed to stop passing traffic.

Even stranger, I noticed that the switch had set itself to transparent
mode. I checked another switch and it also had set itself to
transparent mode. Even more strange, and I'm at a loss to explain this
one, I can no longer access our CatOS switches via SSH. I get the
following message on all of them:

"[Connection to <nameofmyswitch> aborted: error status 29]"

I was not able to make the 2950 work so I just gave up and rebooted
it. That seemed to clear up the problem but I still have another 2950
acting up that I have not rebooted yet. It is one of the switches that
has set itself to transparent mode.

Any thoughts about this? I have no idea what happened and I don't even
know where to begin troubleshooting.

We recently upgraded the 6513 to 12.2(18)SXF4 and, just a few days ago
we upgraded the FWSM to 3.1(1). Perhaps this is a bug in one of those
images. There were some configuration changes made to the FWSM this
morning. I'm going to go inquire about those in a moment.

Any ideas what else to check?

Thanks,
John