CyberHunter
Local dataset, no network
// Other services

Port 522: ULP

Port 522 is assigned by IANA to ulp (ULP).

522

How ulp works

Other services
client:522ulpresponse client:522ulpresponse

The client sends a request to port 522 and the ulp 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 522 dangerous?

We have no specific security note for port 522. 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 522

ServicePortTransportDescriptionReferenceUpdated
ulp 522 TCP, UDP ULP - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 522, and is it reachable?

Linux

sudo ss -ltnup 'sport = :522'      # process listening on 522
sudo lsof -nP -i :522

macOS

sudo lsof -nP -i :522

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 522 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 522
netstat -ano | findstr :522

From another machine

nmap -p 522 -sV <host>
sudo nmap -sU -p 522 <host>
nc -zv <host> 522

Block it in the firewall

sudo ufw deny 522/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 522" -Direction Inbound -LocalPort 522 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 522 used for?

Port 522 is assigned by IANA to ulp (ULP).

Is port 522 TCP or UDP?

Port 522 is registered for TCP and UDP.

Is it safe to open port 522?

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 522 is open?

On Linux run "ss -ltnup 'sport = :522'", on macOS "lsof -nP -i :522", and on Windows "netstat -ano | findstr :522" to see the local process. From another machine, "nmap -p 522 <host>" shows whether it is reachable.

05 Related
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