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I can't seem to get my head wrapped around the purpose of a MIB. I have a collection of ~20 MIB files that were supplied to me by the vendor, but what do I do with them?

I also have a few OID's that were supplied by the vendor that don't seem to be valid. When I issue an "snmpget -v1 -c public 192.168.0.123 .1.4.6.3.2.6.2" (assume that's a valid OID), I get an error indicating the variable is unknown. Does this sound like a hardware configuration problem? Do I need to "load" (for lack of better words) the MIB into the device?

Unfortunately, the vendor has been completely unresponsive with returning emails to my questions, so any help would be greatly appreciated.

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+1 for the question title :-) – Massimo Jan 3 '11 at 16:28
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MIB files are needed to tell you (or your monitoring system, or your SNMP query tool...) what OIDs actually mean; otherwise, all you get is a bunch of numbers. But this is only a client issue, the device you query already knows what OIDs it can accept queries for and what answers it should provide.

If you can't query a device for a given OID, even if the MIB states you should be able to query it, then there could be a MIB mismatch; double check the MIB you're using is actually the right one for that device and its firmware/OS version (SNMP support can change quite a while between firmware releases).

Otherwise, it could also be a configuration problem: maybe the OID you're querying is supported only in some specific configurations, and not in all ones; only the device documentation (or the vendor) can help you here.

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add a .0 to the end of the OID, bet it will work. – SpacemanSpiff Jan 3 '11 at 19:02
@Tom, that's indeed the case for OIDs which represent indexable arrays of data (such as traffic counters for each interface on a router). – Massimo Jan 3 '11 at 22:52
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up vote 2 down vote

instead of snmpget, try to walk it w/ snmpwalk or use snmpgetnext. that will tell you if you need the .0 on the end or not. you don't need mib files to talk to devices. mib files just translate numbers into more meaningful information for people to understand.

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