SNMP: Finding OIDs and MIBs

The key tool in the toolbox for exploring MIBs and finding things in SNMP is either “snmpwalk” or looking at the actual MIB text definitions. On CentOS 5 (and RHEL 5), the net-snmp package installs a default set of MIBs to “/usr/share/snmp/mibs/”.

# snmpwalk -v 2c -c public localhost diskIONReadX

That particular command uses version “2c” of the SNMP protocol to talk to the “public” community on the localhost and looks for “diskIONReadX” (which is a 64bit counter value column from the diskIOTable).

# snmptranslate -m +ALL -IR -Td diskIONReadX

Here, we use “snmptranslate” to report on full details (-Td) of the diskIONReadX property. When looking up SNMP attributes by labels, you’ll want to use the above format, but you can change “-Td” to other “-T” options or a “-O” option. Some common choices are:

# snmptranslate -m +ALL -IR <b>-Td</b> diskIONReadX
UCD-DISKIO-MIB::diskIONReadX
diskIONReadX OBJECT-TYPE
  -- FROM       UCD-DISKIO-MIB
  SYNTAX        Counter64
  MAX-ACCESS    read-only
  STATUS        current
  DESCRIPTION   "The number of bytes read from this device since boot."
::= { iso(1) org(3) dod(6) internet(1) private(4) enterprises(1) ucdavis(2021) ucdExperimental(13) ucdDiskIOMIB(15) diskIOTable(1) diskIOEntry(1) 12 }

# snmptranslate -m +ALL -IR <b>-On</b> diskIONReadX
.1.3.6.1.4.1.2021.13.15.1.1.12

# snmptranslate -m +ALL -IR <b>-Of</b> diskIONReadX
.iso.org.dod.internet.private.enterprises.ucdavis.ucdExperimental.
    ucdDiskIOMIB.diskIOTable.diskIOEntry.diskIONReadX

# snmptranslate -m +ALL -IR <b>-Ou</b> diskIONReadX
enterprises.ucdavis.ucdExperimental.ucdDiskIOMIB.diskIOTable.
    diskIOEntry.diskIONReadX