Port 161 (SNMP)
Simple Network Management Protocol for monitoring network devices (traps on 162).
- Transport
- UDP
- Internet exposure
- Never expose
Should not be reachable from the internet.
Security notes
- Default community strings such as “public” and “private” let anyone read, or change, device settings.
- SNMPv1 and v2c send community strings in cleartext; use SNMPv3.
- Exposed SNMP can also be abused for amplification.
When it shows up in your logs
SNMP queries from outside the management network are reconnaissance.
Related ports
- 162
- 123 NTP