Port 162: SNMP-TRAP
Port 162 receives SNMP traps, the alerts a device sends when something changes, such as a link going down. A monitoring system listens here to react in real time.
| Port number | 162 |
|---|---|
| Service | SNMP trap receiver |
| Protocol | UDP |
| Category | Management |
| Default encryption | No |
How do I check whether port 162 is open?
Port 162 is UDP, which changes the answer: there is no handshake to complete, so nothing outside the host can prove the port is open. Asking the host itself is the reliable route.
| Question | Command | What to know |
|---|---|---|
| Is it open on a remote host? | sudo nmap -sU -p 162 example.com | UDP has no handshake, so there is nothing to complete. nmap infers the state from whether an ICMP port-unreachable comes back, needs root, and is slow and easy to misread. A silent port may be open, filtered, or simply not replying to a probe it does not recognise. |
| What is listening locally? | ss -ulnp | grep ':162 ' | Shows the UDP socket bound to port 162. This is the reliable way to answer the question, because you are asking the host itself rather than guessing from outside. |
Replace example.com with the host you are testing. A blocked port and a port with nothing listening on it look identical from the outside, so if a service should be running, check locally before blaming the firewall.
Frequently asked questions
What is port 162 used for?
Port 162 receives SNMP traps, the alerts a device sends when something changes, such as a link going down. A monitoring system listens here to react in real time.
Is port 162 TCP or UDP?
Port 162 (SNMP-TRAP) uses UDP.
Is port 162 secure?
Port 162 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.
Should I open port 162 on my firewall?
Only if you specifically need SNMP-TRAP. Expose it to the smallest set of trusted sources, and never open database or Windows-service ports to the whole internet.