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// Other services

Port 483: ulpnet

Port 483 is assigned by IANA to ulpnet (ulpnet).

483

How ulpnet works

Other services
client:483ulpnetresponse client:483ulpnetresponse

The client sends a request to port 483 and the ulpnet 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 483 dangerous?

We have no specific security note for port 483. 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 483

ServicePortTransportDescriptionReferenceUpdated
ulpnet 483 TCP, UDP ulpnet - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 483, and is it reachable?

Linux

sudo ss -ltnup 'sport = :483'      # process listening on 483
sudo lsof -nP -i :483

macOS

sudo lsof -nP -i :483

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 483 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 483
netstat -ano | findstr :483

From another machine

nmap -p 483 -sV <host>
sudo nmap -sU -p 483 <host>
nc -zv <host> 483

Block it in the firewall

sudo ufw deny 483/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 483" -Direction Inbound -LocalPort 483 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 483 used for?

Port 483 is assigned by IANA to ulpnet (ulpnet).

Is port 483 TCP or UDP?

Port 483 is registered for TCP and UDP.

Is it safe to open port 483?

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 483 is open?

On Linux run "ss -ltnup 'sport = :483'", on macOS "lsof -nP -i :483", and on Windows "netstat -ano | findstr :483" to see the local process. From another machine, "nmap -p 483 <host>" shows whether it is reachable.

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