2960 switches stop responding.

[andrea.meconi]

Hello.

I have four 2960 running 12.2(55)SE7.

These switches stop responding at the console and vty but other functions are ok.

When I try to connect I receive the banner and no more: no prompt.

Any ideas?

Regards.

Andrea

[Vasilii Mikhailovskii]

Hello.

What authentication (AAA) do you use on the switches?

Do the switches stop responding simultaneously?

Have you tried any other IOS?

[andrea.meconi]

Hello Vasilii.

All switches use AAA with Cisco Secure ACS, which works fine for all other devices, a 2960 also!

Simultaneously? Maybe but I'm so sure.

No, for now I'm looking for a "soft resolution". I cannot power off it.

Many many thanks.

Andrea

[Vasilii Mikhailovskii]

Hello.

I remember there were some bug with AAA on 2960, but I'm not sure.

If you are running RADIUS/TACACS+, try to block the traffic between the switch and authentication server to see if it helps.

[andrea.meconi]

Vasilli,

I think I need to power off the switches.

Regards.

Andrea

[Leo Laohoo]

I have four 2960 running 12.2(55)SE7.

These switches stop responding at the console and vty but other functions are ok.

When you console in do you get an error message like "%Low memory.  Try again later."?

[andrea.meconi]

Hello Leo.

No, I don't get any message, only the banner!

Thanks.

Andrea
 

[Leo Laohoo]

No, I don't get any message, only the banner!

Now this is weird.  Now I've used the exact IOS version you've been using, 12.2(55)SE7, for a year and I haven't seen a problem like this.  

So forgive me to ask you this:  What's the uptime of your switch?

[andrea.meconi]

Many thanks for your time Leo.

Uptime? Some days only.

I changed five switches two weeks ago: same model and same version.

One work fine and the others present this issue.

Regards.

[Leo Laohoo]

Sounds like a configuration issue. 

Do you have SNMP RW community set?  If yes, you can retrieve and/or inject the config using SNMP.

[andrea.meconi]

Maybe Leo!

For one of these switches, I was able to login using local account and verify that AAA model was missed. So I reconfigured and verified it again. I tried to access successffully more and more times. Today I'm not able to login again.

This makes me crazy.

However, there is a very simple configuration onboard. But something goes wrong.

I have a read only access with SNMP.

So, I believe I need to power off and load a new version and a good configuration also.

Regards.

[Leo Laohoo]

I have a read only access with SNMP.

So, I believe I need to power off and load a new version and a good configuration also.

Pull down the configuration of your existing switches with issue (using SNMP) and see if you can replicate the problem on a sand-pit switch.  

If you can, we can definitely do troubleshooting there.  If we find the solution, upgrade the configuration changes using SNMP to the existing switches, however, I don't know how you can do this with SNMP RO.  Are you sure SNMP community string of "private" has been disabled?  Some network switches has this enabled.  (ROFL!)