Guide
Finding the meaning of an SNMP object identifier
SNMP, the protocol behind most network monitoring, names every value on a device with an object identifier: a path of numbers through a global tree. Monitoring tools show those numbers all the time, in graphs, alerts and walks, and they are meaningless without a reference. The page looks up the standard ones in both directions.
How the tree is organised
An OID is read from left to right as a path. Everything under 1.3.6.1 belongs to the Internet. Under it, 1.3.6.1.2.1 is mib-2, the standard management branch; 1.3.6.1.4.1 is “enterprises”, where each organisation registered with IANA has one number and manages its own subtree. A device’s vendor can therefore be read from the number after 1.3.6.1.4.1: Cisco is 9, Microsoft 311 and Net-SNMP 8072. Within mib-2, groups have fixed numbers: system is 1, interfaces is 2, ip is 4, tcp is 6, udp is 7.
What the page covers
The built-in list contains 107 widely used standard objects across the system group, interfaces, IP, TCP, UDP, host resources, entity MIB and the Net-SNMP system statistics. Choose “Numeric OID” and enter a number, or “Object name or word” to search by name or a fragment of one. The page returns the object name with its MIB, a description and, for status objects, the meaning of the values. It does not read MIB files you provide, and anything outside its list, such as a vendor’s private objects, is not named.
Instances and tables
An OID in a walk usually carries extra digits after the object’s own number. If the object is a scalar, the digit is 0: 1.3.6.1.2.1.1.5.0 is the system name. If the object is a column of a table, the extra digits are the index of a row. For the interfaces table that is the interface number, so the same column appears once per interface. The page splits the number into the known object and the remaining instance digits and explains what they usually mean.
A worked example
Press Sample, which loads ifOperStatus.3. The page resolves it to 1.3.6.1.2.1.2.2.1.8, ifOperStatus (IF-MIB) and explains the values: 1 up, 2 down, 3 testing, 5 dormant, 7 lowerLayerDown. The leftover digit “3” is the instance identifier, usually the row index of the table, here interface number 3 (the ifIndex). Searching by name for ifInOctets gives 1.3.6.1.2.1.2.2.1.10, the 32-bit counter of bytes received on an interface.
Limits
The list is a compact selection of common objects, not a full MIB browser. Vendor MIBs and objects in newer standards may be missing, and names are as defined in the original MIB modules. For a device’s own objects load its MIB in a proper tool such as snmptranslate. The page performs a lookup only; it does not talk to a device or send SNMP requests. Convert dotted addresses carried in OIDs with the IPv4 to Integer Converter.
Related tools
- Port Number Lookup shows SNMP uses UDP ports 161 and 162.
- Syslog PRI Calculator decodes the other common monitoring protocol.
- ASN Number Checker classifies BGP autonomous system numbers.
- Network Cable Chart lists the interfaces speeds you will graph with these objects.
Checked against the current version of the SNMP OID Lookup on .