UCD-SNMP Tutorial -- snmptranslate

Note: Much of this tutorial requires ucd-snmp-4.2.2!, so make sure you get it before running the commands found in this tutorial.

Note: A new tutorial for net-snmp 5.0 and above is available as well. The commands is the ucd-snmp specific tutorial will not work as expected if you are using net-snmp and not ucd-snmp.

The snmptranslate tool is a very powerful tool that allows you to browse the MIB tree in various ways from the command line.

In its simplest form, it merely translates a textual oid into a numerical one:

% snmptranslate system.sysUpTime.0
.1.3.6.1.2.1.1.3.0

It can also translate into textual as well, by adding the -On flag to its options

% snmptranslate -On .1.3.6.1.2.1.1.3.0
system.sysUpTime.0

Note that the argument passed can describe a OID in any fashion, and the -On flag merely toggles which type of output is displayed:

% snmptranslate -On .iso.3.6.1.private.enterprises.2021.2.1.prNames.0
enterprises.ucdavis.procTable.prEntry.prNames.0

Note how the oid was abbreviated for you? You can change this behaviour as well with -Of (most useful with the -On flag too):

% snmptranslate -Ofn .iso.3.6.1.private.enterprises.2021.2.1.prNames.0
.iso.org.dod.internet.private.enterprises.ucdavis.procTable.prEntry.prNames.0

The last two commands started with '.' in the beginning of the oid. This is because they were a fully qualified OID starting from the very root of the tree (.1 == .iso).

The first three commands make use of the default prefix that assumes if you don't start with a '.' at the beginning you want a sub section of the mib2 tree. You can change the default prefix by setting the environmental variable PREFIX to be the one you would rather use.

The problem with the above commands is that you have to remember the entire OID for what you're looking for, even with the nice prefix. Now, we wouldn't be a very good package if we didn't provide some sort of random lookup function right? Well, the good news is that we do. -IR nicely does this for us, and searches the MIB tree for the node you want:

% snmptranslate -On sysUpTime.0
Invalid object identifier: sysUpTime.0
% snmptranslate -On -IR sysUpTime.0
system.sysUpTime.0

Finally, starting with version 4.1, it'll even try to do regex pattern matching to find the exact node you want given only a piece of its name by using the -Ib (best match) option:

% snmptranslate -On -Ib 'sys.*ime'
system.sysUpTime

To get a list of all the nodes that match a given pattern, use the -TB flag:

% snmptranslate -On -TB 'vacm.*table'
.iso.org.dod.internet.snmpV2.snmpModules.snmpVacmMIB.vacmMIBObjects.vacmContextTable
.iso.org.dod.internet.snmpV2.snmpModules.snmpVacmMIB.vacmMIBObjects.vacmSecurityToGroupTable
.iso.org.dod.internet.snmpV2.snmpModules.snmpVacmMIB.vacmMIBObjects.vacmAccessTable
.iso.org.dod.internet.snmpV2.snmpModules.snmpVacmMIB.vacmMIBObjects.vacmMIBViews.vacmViewTreeFamilyTable

To get extended information about a mib node, use the -Td (description) flag:

% snmptranslate -Td -Ib 'sys.*ime'
.1.3.6.1.2.1.1.3
sysUpTime OBJECT-TYPE
  -- FROM	SNMPv2-MIB, RFC1213-MIB
  SYNTAX	TimeTicks
  MAX-ACCESS	read-only
  STATUS	current
  DESCRIPTION	"The time (in hundredths of a second) since the network
            management portion of the system was last re-initialized."
::= { iso(1) org(3) dod(6) internet(1) mgmt(2) mib-2(1) system(1) 3 }

Finally, last but certainly not least, if you want a pretty diagram of a section of the mib tree, check out the -Tp flag:

% snmptranslate -Tp system
+--system(1)
   |
   +-- -R-- String    sysDescr(1)
   |        Textual Convention: DisplayString
   +-- -R-- ObjID     sysObjectID(2)
   +-- -R-- TimeTicks sysUpTime(3)
   +-- -RW- String    sysContact(4)
   |        Textual Convention: DisplayString
   +-- -RW- String    sysName(5)
   |        Textual Convention: DisplayString
   +-- -RW- String    sysLocation(6)
   |        Textual Convention: DisplayString
   +-- -R-- Integer   sysServices(7)
   +-- -R-- TimeTicks sysORLastChange(8)
   |        Textual Convention: TimeStamp
   |
   +--sysORTable(9)
      |
      +--sysOREntry(1)
         |
         +-- ---- Integer   sysORIndex(1)
         +-- -R-- ObjID     sysORID(2)
         +-- -R-- String    sysORDescr(3)
         |        Textual Convention: DisplayString
         +-- -R-- TimeTicks sysORUpTime(4)
                  Textual Convention: TimeStamp

As a homework assignment, we'll leave it up to you to run snmptranslate -Tp without an oid argument, which prints the known MIB tree in its entirety.