CyberHunter
Local dataset, no network
// Other services

Port 54: XNS Clearinghouse

Port 54 is assigned by IANA to xns-ch (XNS Clearinghouse).

54

How xns-ch works

Other services
client:54xns-chresponse client:54xns-chresponse

The client sends a request to port 54 and the xns-ch 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 54 dangerous?

We have no specific security note for port 54. 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 54

ServicePortTransportDescriptionReferenceUpdated
xns-ch 54 TCP, UDP XNS Clearinghouse - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 54, and is it reachable?

Linux

sudo ss -ltnup 'sport = :54'      # process listening on 54
sudo lsof -nP -i :54

macOS

sudo lsof -nP -i :54

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 54 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 54
netstat -ano | findstr :54

From another machine

nmap -p 54 -sV <host>
sudo nmap -sU -p 54 <host>
nc -zv <host> 54

Block it in the firewall

sudo ufw deny 54/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 54" -Direction Inbound -LocalPort 54 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 54 used for?

Port 54 is assigned by IANA to xns-ch (XNS Clearinghouse).

Is port 54 TCP or UDP?

Port 54 is registered for TCP and UDP.

Is it safe to open port 54?

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 54 is open?

On Linux run "ss -ltnup 'sport = :54'", on macOS "lsof -nP -i :54", and on Windows "netstat -ano | findstr :54" to see the local process. From another machine, "nmap -p 54 <host>" shows whether it is reachable.

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