I understand SNMP agent on a server collects information such as CPU, Memory, Network, IO stat ... information. How to I know what exactly information being collecting on a linux server by SNMP agent?
closed as not a real question by ewwhite, Wesley, Tom O'Connor, Khaled, MDMarra May 13 '12 at 18:28
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Well if you don't have access to the application that is doing the query, then I'd start by performing a packet capture. Though some SNMP implementations support TLS, the vast majority just use plain latest UDP, so finding the OIDs queried should be fairly easy once you have a packet capture.
The various MIB files that come with Net-SNMP tell you what values might possibly be available. Using
snmptranslate you can see a tree view of the different values under the
ucdavid subtree (which contains the Net-SNMP specific values):
snmptranslate -m ALL -Tp -OS iso.org.dod.internet.private.enterprises.ucdavis
To get a description of one individual entry (e.g. lmVoltSensorsValue), do:
snmptranslate -m ALL -Td -On -IR lmVoltSensorsValue
Note that probably not all fields are really available. Some might be platform-specific, others deprecated and some are only available if configured.
The above snmptranslate examples only work if the MIB files are installed and if all the paths are correctly set, but this is out of the scope of this question.
Read the source? Read the documentation. That's about all you can do.