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// Other services

Port 281: Personal Link

Port 281 is assigned by IANA to personal-link (Personal Link).

281

How personal-link works

Other services
client:281personal-linkresponse client:281personal-linkresponse

The client sends a request to port 281 and the personal-link 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 281 dangerous?

We have no specific security note for port 281. 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 281

ServicePortTransportDescriptionReferenceUpdated
personal-link 281 TCP, UDP Personal Link - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 281, and is it reachable?

Linux

sudo ss -ltnup 'sport = :281'      # process listening on 281
sudo lsof -nP -i :281

macOS

sudo lsof -nP -i :281

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 281 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 281
netstat -ano | findstr :281

From another machine

nmap -p 281 -sV <host>
sudo nmap -sU -p 281 <host>
nc -zv <host> 281

Block it in the firewall

sudo ufw deny 281/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 281" -Direction Inbound -LocalPort 281 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 281 used for?

Port 281 is assigned by IANA to personal-link (Personal Link).

Is port 281 TCP or UDP?

Port 281 is registered for TCP and UDP.

Is it safe to open port 281?

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 281 is open?

On Linux run "ss -ltnup 'sport = :281'", on macOS "lsof -nP -i :281", and on Windows "netstat -ano | findstr :281" to see the local process. From another machine, "nmap -p 281 <host>" shows whether it is reachable.

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