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// Other services

Port 181: Unify

Port 181 is assigned by IANA to unify (Unify).

181

How unify works

Other services
client:181unifyresponse client:181unifyresponse

The client sends a request to port 181 and the unify service answers.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Well-known (0-1023)
Category
Other services
01 Security

Is port 181 dangerous?

We have no specific security note for port 181. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 181

ServicePortTransportDescriptionReferenceUpdated
unify 181 TCP, UDP Unify - 2012-07-31

// source: IANA service name and port number registry

03 Check it

Which program uses port 181, and is it reachable?

Linux

sudo ss -ltnup 'sport = :181'      # process listening on 181
sudo lsof -nP -i :181

macOS

sudo lsof -nP -i :181

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 181 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 181
netstat -ano | findstr :181

From another machine

nmap -p 181 -sV <host>
sudo nmap -sU -p 181 <host>
nc -zv <host> 181

Block it in the firewall

sudo ufw deny 181/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 181" -Direction Inbound -LocalPort 181 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 181 used for?

Port 181 is assigned by IANA to unify (Unify).

Is port 181 TCP or UDP?

Port 181 is registered for TCP and UDP.

Is it safe to open port 181?

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. Close the port if nothing on the host needs it.

How do I check if port 181 is open?

On Linux run "ss -ltnup 'sport = :181'", on macOS "lsof -nP -i :181", and on Windows "netstat -ano | findstr :181" to see the local process. From another machine, "nmap -p 181 <host>" shows whether it is reachable.

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