Networking
Risk: High
Port 161 — SNMP (Simple Network Management Protocol)
Port 161 is used by SNMP agents to listen for monitoring requests, telemetry queries, and device status polls from Network Management Stations (NMS).
PORT NUMBER
161
PROTOCOL
UDP
DEFAULT PROCESS
snmpd
FIREWALL TARGET
161/udp
Instant Terminal Fixes for Port 161
macOS & Linux Terminal
1. Check who is listening on port 161:
sudo ss -ulpn | grep ":161 "2. Kill process occupying port 161 (EADDRINUSE fix):
sudo systemctl stop snmpd3. UFW Firewall Allow rule:
sudo ufw allow from 10.0.0.0/8 to any port 161 proto udpWindows PowerShell (Admin)
1. Check listening port:
Get-NetUDPEndpoint -LocalPort 1612. Force kill process on port 161:
Stop-Service SNMP -Force3. Docker Port Forwarding Mapping:
docker run -d -p 161:161/udp prom/snmp-exporterCommon Error Encountered
Timeout: No Response from host on UDP port 161 (snmpwalk timed out).
Security Advisory & Hardening
SNMP v1 and v2c use plaintext community strings (frequently default to "public"), exposing network topologies and hardware details. Upgrade to SNMPv3 with authPriv encryption.
Frequently Asked Questions
Port 161 Questions & Answers
Common questions regarding default services, kill commands, and firewall configurations.
Port 161 is commonly used for SNMP (Simple Network Management Protocol). Port 161 is used by SNMP agents to listen for monitoring requests, telemetry queries, and device status polls from Network Management Stations (NMS).