UDP Port 161 – SNMP (Simple Network Management Protocol)
About UDP Port 161
Port 161 carries the IANA assignment for snmp. The IANA description reads: ‘SNMP’. This port appears in 14 IDS rules and does not have notable malware activity indicators in our data.
IDS Rule References
14 IDS / security rules reference UDP port 161. Treat that number as context, not a danger score. Many detection rules are written against groups of ports rather than one service, web ports especially, so common web alternate ports inherit large counts while genuinely sensitive services can show few rules or none. Presence in IDS rules does not mean traffic on this port is malicious.
Rule categories (top 4): misc-attack (6), attempted-recon (5), attempted-admin (2), attempted-dos (1).
Sample rule descriptions for UDP port 161:
- SERVER-OTHER Bay/Nortel Nautica Marlin
- PROTOCOL-SNMP NT UserList
- PROTOCOL-SNMP community string buffer overflow attempt
- PROTOCOL-SNMP public access udp
- PROTOCOL-SNMP private access udp
Data Sources
This information is compiled from: IANA Service Name and Transport Protocol Port Number Registry, Emerging Threats Open Ruleset (BSD 2-Clause / GPLv2 per SID range), and Snort Community Rules (GPLv2).