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// Remote access

Port 5161: SNMP over SSH Transport Model

Port 5161 is assigned by IANA to snmpssh (SNMP over SSH Transport Model).

5161

How snmpssh works

Remote access
terminal:5161snmpssh terminal:5161snmpssh

The client opens a session to port 5161: each command typed is sent to the server, which runs it and returns the output.

Transport
TCP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Remote access
01 Security

Is port 5161 dangerous?

We have no specific security note for port 5161. Its risk depends on the program actually listening on it. General advice for remote access services:

  • Do not expose remote administration directly: use a VPN or a zero-trust access proxy.
  • Require MFA or key-based authentication and lock out brute-force attempts.
  • Log every login and alert on new source addresses.
02 Registry

IANA registry entries for port 5161

ServicePortTransportDescriptionReferenceUpdated
snmpssh 5161 TCP SNMP over SSH Transport Model RFC 5592 -
-5161-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 5161, and is it reachable?

Linux

sudo ss -ltnup 'sport = :5161'      # process listening on 5161
sudo lsof -nP -i :5161

macOS

sudo lsof -nP -i :5161

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 5161 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 5161
netstat -ano | findstr :5161

From another machine

nmap -p 5161 -sV <host>
nc -zv <host> 5161

Block it in the firewall

sudo ufw deny 5161/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 5161" -Direction Inbound -LocalPort 5161 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 5161 used for?

Port 5161 is assigned by IANA to snmpssh (SNMP over SSH Transport Model).

Is port 5161 TCP or UDP?

Port 5161 is registered for TCP.

Is it safe to open port 5161?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Do not expose remote administration directly: use a VPN or a zero-trust access proxy.

How do I check if port 5161 is open?

On Linux run "ss -ltnup 'sport = :5161'", on macOS "lsof -nP -i :5161", and on Windows "netstat -ano | findstr :5161" to see the local process. From another machine, "nmap -p 5161 <host>" shows whether it is reachable.

05 Related
:22 SSH tcp · udp · sctp · moderate risk :3389 RDP tcp · udp · critical risk :23 Telnet tcp · udp · critical risk :5900 VNC tcp · udp · critical risk :5985 WinRM (HTTP) tcp · udp · high risk :5986 WinRM (HTTPS) tcp · udp · high risk :10000 Webmin tcp · udp · high risk :89 SU/MIT Telnet Gateway tcp · udp

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