[mrtg] graphing an OID

[Steve Shipway]

Here's a few things to check:

1. Make sure you are giving the OIDs in the correct form.  IE, two of
them, no leading '.', add the trailing '.0' if required.
2. Make sure that you have escaped any special characters in the
community string
3. Make sure that the OID returns a NUMBER, preferably a COUNTER.
4. If the OID does not return a total counter, make sure you have
Options[]:gauge set, else you get constant zeroes.
5. Make sure that you have MaxBytes (and, if necessary, AbsMax) set to a
sensible level else the returned value will be rejected.  Set it to
something huge if you're not sure.  Don't set AbsMax unless you have to.
6. Make sure no error messages come from MRTG indicating an incorrect
community string or no access to the device in question. MRTG's error
messages can by a bit cryptic, but they can give you the cause if you
know how to read them.
7. Use SNMPWALK to verify that the OID exists, and has the full number
you expect, and returns the data type you expect.

Hope this helps,

Steve