Complete SNMP OID Catalog: Every Sensor & Metric

By the SNMP Monitoring team · Reviewed July 2026

This is the page to bookmark. One consolidated reference of the SNMP OIDs you actually reach for — CPU, memory, disk, interfaces, physical sensors, and common devices — each mapped to its MIB, base OID, and unit, with a link to the page that goes deep. The table is organised by category so you can jump to a family and copy the object you need. Everything here is a standard MIB object unless noted; vendor-specific metrics live under the enterprise arc and are called out as such.

Parent: sensors. For the "how do I alert on this" side, every row's detail page links to its how-to twin in monitoring.

How to use this catalog

The workflow is always the same four moves:

1. Find the category below — system, network, physical, or device.
2. Copy the base OID for the metric you want.
3. Test it on the device with snmpwalk/snmpget before wiring it into anything.
4. Implement via the matching how-to page in /monitoring/.

Rule that saves you: always walk an OID on the actual box before templating it. Vendors differ, agents omit MIBs, and a copied OID that resolves on one device returns nothing on another.

System OIDs

CPU, memory, disk, uptime, processes and load — mostly HOST-RESOURCES-MIB (1.3.6.1.2.1.25) with UCD-SNMP for load average.

Note the two "uptime" objects: hrSystemUptime (…25.1.1.0) tracks OS uptime, while sysUpTime (1.3.6.1.2.1.1.3.0) is the agent's timer — handy for reboot detection.

Network OIDs

Interface counters and status from the IF-MIB (1.3.6.1.2.1.2 and the extended .31). Full column list on the interface reference.

Physical / hardware sensor OIDs

Generic physical sensors come through the ENTITY-SENSOR-MIB (1.3.6.1.2.1.99), where one object holds the value and companions hold the type and scale:

• entPhySensorValue — 1.3.6.1.2.1.99.1.1.1.4 — the reading (integer)
• entPhySensorType — …99.1.1.1.1 — celsius, rpm, voltsDC, voltsAC, amperes, watts, percentRH…
• entPhySensorScale — …99.1.1.1.2 — SI multiplier (e.g. milli)
• entPhySensorPrecision — …99.1.1.1.3 — decimal places

Because one object serves every physical quantity, the type tells you whether a reading is a temperature, a fan RPM or a rail voltage. Details: temperature, fan speed, power, humidity & airflow.

Device OIDs

Dedicated device MIBs for UPS, printer and protocol stacks; RAID and PDU specifics are largely vendor enterprise objects.

Master reference table

The consolidated view — the single table most people copy from. The ostr.io column flags metrics the external monitoring service reads over agentless SNMPv2c.

The ✅ rows are what an external SNMPv2c poller like ostr.io reads agentlessly — uptime, sessions, processes, load, CPU, storage and interfaces — the "is this box alive and healthy from the outside" set.

Testing an OID

Before you trust any row, prove it on the device:

snmpget -v2c -c <RO_string> <host> 1.3.6.1.2.1.1.3.0
snmpwalk -v2c -c <RO_string> <host> 1.3.6.1.2.1.25.2.3.1

SNMPv2-MIB::sysUpTime.0 = Timeticks: (884213700) 102 days, 8:22:17.00
HOST-RESOURCES-MIB::hrStorageDescr.1 = STRING: Physical memory
HOST-RESOURCES-MIB::hrStorageSize.1 = INTEGER: 4014276
HOST-RESOURCES-MIB::hrStorageUsed.1 = INTEGER: 3211220

An empty result means the agent doesn't implement that MIB, an ACL/view is hiding it, or the OID is wrong for this device — not that the metric is zero. <RO_string> is a placeholder; keep live communities out of committed scripts.

Frequently asked questions

What are the most common SNMP OIDs?

The everyday set: hrProcessorLoad (1.3.6.1.2.1.25.3.3.1.2) for CPU, the hrStorageTable rows (1.3.6.1.2.1.25.2.3.1.5/.6) for memory and disk, sysUpTime (1.3.6.1.2.1.1.3.0) for uptime, and the IF-MIB counters (ifHCInOctets 1.3.6.1.2.1.31.1.1.1.6) for interfaces. Those cover most host and network dashboards.

What OID is CPU, disk, or uptime?

CPU is hrProcessorLoad at 1.3.6.1.2.1.25.3.3.1.2 (per core). Disk/memory capacity and usage are the hrStorageTable columns 1.3.6.1.2.1.25.2.3.1.5 (size) and .6 (used). Uptime is sysUpTime at 1.3.6.1.2.1.1.3.0, or hrSystemUptime at 1.3.6.1.2.1.25.1.1.0 for OS uptime.

How do I test an OID?

Use snmpget for a single scalar (with its trailing instance, e.g. .0) and snmpwalk to traverse a table or subtree. If the object returns nothing, the agent may not implement that MIB or a view is filtering it — walk the parent branch and check names with a MIB browser.

Where do vendor OIDs live?

Under the enterprise arc 1.3.6.1.4.1, followed by the vendor's assigned number. Anything a standard MIB doesn't cover — RAID health, a specific PDU outlet, a labelled CPU-temperature sensor — is typically found there, and you need that vendor's MIB to interpret it.

Key takeaways

• Bookmark this page — it's the copy-paste master OID table for the site.
• System = HOST-RESOURCES (…25); network = IF-MIB (…2/.31); physical = ENTITY-SENSOR (…99); UPS/printer have their own MIBs; vendor extras under 1.3.6.1.4.1.
• Always test an OID with snmpwalk before templating — empty ≠ zero.
• The ✅ rows are what an agentless external check reads over SNMPv2c via external monitoring.
• Each row links to its detail page; from there to the how-to twin in monitoring.