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TUT:snmptranslate
The SNMP protocol tends to work with numeric OIDs and raw values. One of the main roles of the MIB files is to convert these into more meaningful textual names and sensibly formatted values.
While most of the Net-SNMP command-line applications can control how the
results of an SNMP query are displayed, there is one tool
(snmptranslate) which can be used
standalone, simply displays information drawn from the MIB files
themselves.
See TUT:Using and loading MIBS.
In its simplest form, snmptranslate takes a numeric OID and displays
the corresponding textual MIB name:
% snmptranslate .1.3.6.1.2.1.1.3.0
SNMPv2-MIB::sysUpTime.0
It can also perform the reverse translation, taking the textual MIB name
and displaying the numeric OID. This uses the -On flag:
% snmptranslate -On SNMPv2-MIB::sysUpTime.0
.1.3.6.1.2.1.1.3.0
There are several other ways of displaying an OID, which are described
in
TUT:Customized_Output_Formats.
One of these is to show the full list of MIB subidentifier names, using
the -Of flag:
% snmptranslate -Of SNMPv2-MIB::sysUpTime.0
.iso.org.dod.internet.mib-2.system.sysUpTime.0
Note that these flags determine how the OID should be displayed, regardless of how it was originally specified:
% snmptranslate .iso.3.6.1.private.enterprises.2021.2.1.prNames.0
NET-SNMP-MIB::prNames.0
% snmptranslate -On .iso.3.6.1.private.enterprises.2021.2.1.prNames.0
.1.3.6.1.4.1.2021.2.1.2.0
% snmptranslate -Of .iso.3.6.1.private.enterprises.2021.2.1.prNames.0
.iso.org.dod.internet.private.enterprises.ucdavis.procTable.prEntry.prNames.0
The examples above identified a particular object, either by providing
the full list of MIB subidentifiers (numeric, textual or a mixture), or
by specifying the relevant MIB module containing the desired MIB object.
However MIB objects are guaranteed to be unique within IETF standard
MIBs (and are rarely duplicated across vendor-supplied MIBs either). So
it would usually be sufficient to simply give the bare MIB object name,
with no further qualifications. Snmptranslate uses the -IR flag to
do this "random-access" lookup:
% snmptranslate sysUpTime.0
Invalid object identifier: sysUpTime.0
% snmptranslate -IR sysUpTime.0
SNMPv2-MIB::sysUpTime.0
(The other commands do this by default - only snmptranslate needs it
to be explicitly turned on).
It's even possible to provide a regex pattern, and have snmptranslate
(or the other command-line tools) do a "best-match" search to find the
appropriate MIB object. This uses the -Ib flag:
% snmptranslate -Ib 'sys.*ime'
system.sysUpTime
However these approaches do run the risk (however slight) of selecting the wrong MIB object. It's safest to use one of the earlier forms.
To get a list of all the nodes that match a given pattern, use the -TB
flag:
% snmptranslate -TB 'sys.*ime'
SNMPv2-MIB::sysORUpTime
SNMPv2-MIB::sysUpTime
HOST-RESOURCES-MIB::hrSystemUptime
To get extended information about a particular MIB node, use the -Td
flag to display the full description from the MIB
file:
% snmptranslate -On -Td SNMPv2-MIB::sysUpTime
.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 }
This can be combined with the other flags described earlier:
% snmptranslate -On -Td -IR sysUpTime
% snmptranslate -On -Td -Ib 'sys.*ime'
to give the same results.
Finally, it's possible to display a formatted diagram of a selected
subset of the MIB tree, using the -Tp flag:
% snmptranslate -Tp -IR 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
This shows the accessibility (read-only, or read-write), syntax, name and subidentifier of each MIB object within the specified subtree, together with the internal structure of those MIB objects.
Running snmptranslate -Tp without an OID argument will display this
information for the known MIB tree in its entirety. This is left as an
exercise for the student!