SNMPV3 not working via loopback

[alcashite]

Hi,

We have some 6860s that we are monitoring through Solarwinds. We have some that have been deployed that we cannot get SNMP working on. I have done some testing and found that I can successfully read SNMPV3 via one of the gateway addresses on the device but when trying to poll when using our Loopback0 interface IP address the request fails. I can't see anything in the config that would be causing this. I have compared the config to a working switch and nothing is different yet SNMP doesn't work on the loopback.

It seems to me it is a problem on the switch rather than the network between as I am able to connect using the gateway address. The loopback0 interface IP is being used to manage to switch so don't think it is a connectivity issue with that either. Any ideas?

Thanks

[silvio]

Is there any firewall between the switch and the server (maybe unsymetric routing is forbidden)

Per default the Loopback0 interface should be the source - but you can check it and config it:

Code: Select all

show ip service source-ip
ip service source-ip loopback0 snmp

regards
Silvio

[alcatelro]

Hi Silvio,


Thank you for your help, I am one of alcashite's colleagues, ip service source-ip loopback0 snmp fixed most of our 6860s, we still have 2 6860s we cannot monitor trough Orion Solarwinds, we think is a problem with the monitoring system itself, no idea at the moment as the config is the same everywhere, also tried to remove and reapply the config.

Code: Select all

show ip service source-ip 
Legend: - no explicit configuration

Application   Interface-name
-------------+--------------------------------
dns           -
ftp           -
ldap          -
ntp           -
radius        -
sflow         -
snmp          Loopback0
ssh           -
swlog         -
tacacs        -
telnet        -
tftp          -

[silvio]

delete all the snmp config and the snmp user, and create all off them again. Mostly there is a little typing error.
regards
Silvio

[alcatelro]

Thank you Silvio, we tried to remove the config and create again before, it must be something else wrong we cannot see. Is it any way to check the logs or to enable debugging for snmp? Regards

[silvio]

show snmp statistic...etc.

try with snmp v1, or snmp v3 - only md5 (no encryption, check the used udp port, mirror/monitor the traffic (wireshark).....
a lot of possibilities

regards
Silvio