Intermittent links on Cisco 4006

[thechunman]

We have two Cisco Catalyst 4006 connecting two buildings through Fiber. Each houses 48-ports 10/100 autosensing modules for client connects. A month ago a strange problem started where some users in building 2 would drop connections or hang when accessing resources in building 1. Meanwhile no one in building 1 has any problem. Our domain server resides in building 1 and there's a BDC in building 2. When I logged in to the BDC during the problem I can ping to most resources except for my file server. It also has problem pinging the secondary DNS which is in a different subnet. I telnet into the switch and it has no problem pinging the main file server. After a while everything would eventually be fine. Then after a while the cycle starts again. Note that not everyone in building 2 is affected. We cannot find any common denominators among the affected users/PCs. Switch ports on the affected PC didn't help.

There're no error in the error log and the bootup diagnostics look fine. We have no vlan setup, just the default with everyone in it. Most settings are default from Cisco. Did not enable switchacceleration.

Any ideas?

[glen.grant]

What version code are you using , awhile back there was a problem where people even in the same vlan would stop talking to each other , this was a code problem . In the 6.X train you need to be above 6.2.3 I believe, not sure about the 5.X (5.5.10) I believe . Here is the bug.

On a Catalyst 4006 with a SupII switch engine, switch ports in the

same VLAN may lose connectivity with one another.

The loss of connectivity results in a VLAN appearing to be partitioned

into several isolated segments. A host may be able to ping one set of

devices in its VLAN, while it can not ping another set of devices in

the same VLAN.

This loss of connectivity is independent of the slot that a linecard

is installed in, i.e. the same set of ports on a given linecard are

affected regardless of the slot that the linecard is installed in.

The workaround is to reset the switch.

This problem has a software work-around in versions 5.5(7), 6.1(3), 6.2(1)

and later. This software fix for this issue will be in 5.5(10), 6.2(3), 6.3(1)

and later.

[thechunman]

Here are my versions for the switch in building 2:

Hw : 3.2

Gsp: 6.3(4.0)

Nmp: 6.3(4)

in building 1:

Hw : 3.1

Gsp: 6.3(4.0)

Nmp: 6.3(4)

So the version should be OK.

[thechunman]

The problem continues. I just replaced the supervisor module and reseated all the modules again. However as I pulled out the switch I noticed lots of dust accumulation inside the switch and on the module. Spent a good deal of time blowing off all the dust. Appears that construction was done near the switch and caused that situation. After restarting people seems OK for now. Anyway can this be a cause to my problem?