Search over 40 common SNMP Object Identifiers used in network monitoring. Find OIDs for system info, interfaces, CPU, memory, bandwidth, and more — with MIB references and usage examples.
| OID | Name | Type | MIB | Description |
|---|
SNMP (Simple Network Management Protocol) is the standard protocol for monitoring network devices — routers, switches, firewalls, and servers. Every monitored metric is identified by a unique Object Identifier (OID), which is a dotted-decimal string like 1.3.6.1.2.1.1.1.0.
When you configure monitoring tools like Nagios, Zabbix, PRTG, or LibreNMS to watch your router or switch, you need the correct OIDs to collect the right data. This reference covers the most commonly used OIDs across standard MIBs.
Before querying OIDs, understand which SNMP version your devices support. Using SNMPv3 is strongly recommended for network security:
| Feature | SNMPv1 | SNMPv2c | SNMPv3 |
|---|---|---|---|
| Authentication | Community string (plaintext) | Community string (plaintext) | Username + password (encrypted) |
| Encryption | None | None | AES/DES encryption |
| 64-bit Counters | No | Yes | Yes |
| Security Level | Low | Low | High |
| Recommended | No | Only on isolated networks | Yes — always prefer |
Use these commands to query OIDs from your network devices. Replace community with your SNMP community string and device-ip with the device's IP address:
# Get a single OID value
snmpget -v2c -c community device-ip 1.3.6.1.2.1.1.1.0
# Walk an OID tree
snmpwalk -v2c -c community device-ip 1.3.6.1.2.1.2.2
# Bulk get (faster for multiple OIDs)
snmpbulkget -v2c -c community device-ip 1.3.6.1.2.1.2.2.1
# SNMPv3 with authentication
snmpget -v3 -u myuser -l authPriv -a SHA -A mypass -x AES -X myencpass device-ip 1.3.6.1.2.1.1.1.0# Using SnmpSharpNet or third-party tools
# Or install net-snmp for Windows
snmpget -v2c -c community device-ip 1.3.6.1.2.1.1.1.0Pro Tip: Never use the default community strings
public(read) andprivate(write) in production. Change them immediately and restrict SNMP access to your monitoring server's IP using ACLs on each device. Better yet, use SNMPv3 with authentication and encryption. For firewall rules, SNMP uses UDP port 161 — verify it's accessible with our Port Checker.
Interface OIDs are the most frequently polled for bandwidth monitoring. The ifInOctets and ifOutOctets counters let you calculate throughput by comparing values over time:
| OID | Name | Use Case | Notes |
|---|---|---|---|
ifInOctets | Bytes In | Incoming bandwidth | 32-bit, wraps at ~4 GB |
ifOutOctets | Bytes Out | Outgoing bandwidth | 32-bit, wraps at ~4 GB |
ifHCInOctets | Bytes In (64-bit) | High-speed links | Use for > 100 Mbps links |
ifHCOutOctets | Bytes Out (64-bit) | High-speed links | Use for > 100 Mbps links |
ifOperStatus | Link Status | Up/down monitoring | 1=up, 2=down |
ifInErrors | Input Errors | Cable/port issues | Increasing = problem |
To calculate bandwidth usage from counter OIDs, poll the value at two points in time and compute the difference:
# Bandwidth formula:
# bps = (counter2 - counter1) * 8 / (time2 - time1)
# Example: ifHCInOctets
# Poll 1 at t=0: ifHCInOctets = 1000000000
# Poll 2 at t=300: ifHCInOctets = 1375000000
# Bytes diff = 375000000
# Bits = 375000000 * 8 = 3000000000
# bps = 3000000000 / 300 = 10000000 = 10 MbpsUse our Bandwidth Calculator to convert between units or our IOPS Bandwidth Converter for storage metrics.
Beyond network interfaces, SNMP can monitor server health including CPU, memory, and disk usage. These OIDs come from the HOST-RESOURCES-MIB, supported by most operating systems with an SNMP agent installed:
hrProcessorLoad gives per-CPU percentage utilizationhrMemorySize for total RAM, combine with hrStorageUsed for usagehrStorageSize and hrStorageUsed for each storage volumehrSystemUptime for OS uptime (differs from sysUpTime which is SNMP agent uptime)An OID (Object Identifier) is a unique dotted-decimal number that identifies a specific piece of data on an SNMP-managed device. For example, 1.3.6.1.2.1.1.5.0 (sysName) returns the hostname of the device. OIDs are organized in a tree structure defined by MIBs.
Start with the standard OIDs listed above — they work on most devices. For vendor-specific OIDs (like Cisco CPU or Ubiquiti signal strength), download the manufacturer's MIB files and use snmptranslate or a MIB browser to explore them.
sysUpTime measures how long the SNMP agent has been running — it resets if the SNMP service restarts. hrSystemUptime measures the operating system uptime since last boot. For accurate uptime monitoring, use hrSystemUptime.
32-bit counters (Counter32) wrap at 4,294,967,295. On a 1 Gbps link, ifInOctets wraps every ~34 seconds. Switch to 64-bit HC counters (ifHCInOctets) which won't wrap for thousands of years at any practical speed.
SNMPv1 and v2c send community strings in plaintext — not secure. SNMPv3 adds authentication (SHA/MD5) and encryption (AES/DES). Always use SNMPv3 and restrict SNMP access to monitoring server IPs using ACL rules.
SNMP uses UDP port 161 for agent queries and UDP port 162 for traps (notifications). Ensure these ports are open between your monitoring server and managed devices. Use our Port Checker to verify.
Most consumer routers don't support SNMP. Routers running OpenWrt, DD-WRT, or advanced firmware often do. Enterprise and prosumer routers (MikroTik, Ubiquiti, pfSense) have full SNMP support. Log into your router and check for SNMP settings.
About Tommy N.
Tommy is the founder of RouterHax and a network engineer with 10+ years of experience in home and enterprise networking. He specializes in router configuration, WiFi optimization, and network security. When not writing guides, he's testing the latest mesh WiFi systems and helping readers troubleshoot their home networks.
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