Catalyst 2950's becomming transparent

[malw11163]

I am experiencing issues with Catalyst 2950's both 24 and 48  port switches.

They cannot be accessed via their management interface, but access to switches connected through the transparent

one is possible.

CDP fails to show the transparent switch, traffic flows through, users access not affected.

The interface shows up, but the switch IP fails to respond to pings.

Logs do not display any errors, when box is bounced all functionality restored.

Any ideas as to the cause ?

Many Thanks

M,

[Peter Paluch]

Hello,

What do you mean by "when box is bounced" - you mean reloaded?

What IOS version are you running? Is it possible for you to upgrade to the latest available IOS for these switches?

Best regards,

Peter

[malw11163]

Hi Peter,

Thanks for the fast responce.

Yes I mean once the device is reloaded management connectivity is restored.

IOS version is 12.1(22)EA8

Will update as last resort.

Thanks

Malcolm

[Peter Paluch]

Hi Malcolm,

The fact is that we are most probably not hunting a configuration error. For example, the CDP is almost an unconfigurable protocol. You can activate or deactivate it, change the version and default timer, but that's about it. If a switch suddenly stops appearing in CDP tables of its neighbors, just so, that is an issue that most probably points towards an IOS bug (or an attack).

Assuming that you have logging buffered configured on the 2950 switches exhibiting these symptoms, are there any logging messages recorded that might bring more light into this issue? Check the show logging output please. Also, how often do these problems appear?

For your information, the latest IOS available for your platform is 12.1(22)EA14.

Best regards,

Peter

[malw11163]

Hi Peter,

IOS has been upgraded to latest version.

Switches still exhibiting the problems, logs reflect no issue.

Users attached to the device not affected at all. The 35 & 3700 series switches not affected at all ?

The problem occurs intermittently, no discernable patten can be identified, first indication is when

snmp alarms are activated. As mentioned above the users function as normal, only the management

interface goes down, no IP address conflict, CDP fails to pick up the switch but the show interface

shows the link to be up ?

Any additional suggestions would be appreciated.

Thanks for all your suggestions so far.

Regards

Malcolm

[glen.grant]

  Sounds like a link that may be going unidirectional once in awhile , (bad pair) . Possible link going err-disable due to errors ?  No cdp , cant address that , have never seen that if the link is good .  Could be a faulty unit.