SNMP not working in SG300-28

[BRYAN HUNT]

Hello,

We have several of the SG300 series of switches.  All seem to work fine with SNMP.

We have one SG300-28 however that will not response to SNMP requests.

We have:

snmp-server server
snmp-server community READSNMP ro view DefaultSuper

set in the config.

We have upgraded the firmware to: 1.4.5.02, did not help.

Does anyone have an idea on what we can/should try next?

Thanks.

Bryan Hunt

[Marvin Rhoads]

Have you spanned the upstream port that is sending the SNMP requests and confirmed they are getting to the switch?

Have you confirmed that the switch's management interface can communicate with the management system?

I try to use something like an ssh connection initiated from the switch to confirm symmetric routing with the tcp 3-way handshake completing.

[BRYAN HUNT]

Marvin,

Thanks for the response.

The switch is remote, so have not been able to do a packet capture off of a mirrored port.  But, we can touch the switch via SSH and HTTPS, so I know that it is reachable from our site.  And have confirmed that the UDP port 161 request leaves our firewall to go to the remote switch.

I have tried  serveral different SNMP tools to interrogate this switch.  The latest is a simple SNMP walk tool.  No resonse from the switch.

Thanks.

Bryan Hunt

[Marvin Rhoads]

Hmm ok - I agree it sounds like the connectivity prerequisites are in place.

Since you can ssh in, I'd pull the running configuration and put it side by side with a working one's config using a tool like examdiff to spot anything relevant that might have been left out of the configuration. More than once I've overlooked some single line in the config and found it by using a tool that acts like an extra pair of (sharper) eyes.

You're running SNMPv2 - right? I ask because v3 settings have some bits that don't show up in the running config but only when you use "show snmp users" command and such. 

[BRYAN HUNT]

Just tried to do a v1 MIB walk right now...   Have not tried 2c or 3 yet.

[Vinod Arya]

If this is your complete SNMP config on the device, you have mapped the community with a view DefaultSuper which needs to be configured.

Just try to remove the view setting and see if you're able to poll. Config :

1. no snmp-server community READSNMP ro view DefaultSuper

2. snmp-server community READSNMP ro 

Try if that works. Also, to see the packets are reaching the device, collect multiple output of show snmp while polling.

[BRYAN HUNT]

Vinod,

I had tried both Default and DefaultSuper in the past.  I set it back to Default and tried again, no luck.

I used the show snmp command.  That seemed to only show the snmp config settings?  Not any kind of traffic?

Thanks.

Bryan Hunt