CyberHunter
Local dataset, no network
// Other services

Port 553: pirp

Port 553 is assigned by IANA to pirp (pirp).

553

How pirp works

Other services
client:553pirpresponse client:553pirpresponse

The client sends a request to port 553 and the pirp 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 553 dangerous?

We have no specific security note for port 553. 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 553

ServicePortTransportDescriptionReferenceUpdated
pirp 553 TCP, UDP pirp - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 553, and is it reachable?

Linux

sudo ss -ltnup 'sport = :553'      # process listening on 553
sudo lsof -nP -i :553

macOS

sudo lsof -nP -i :553

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 553 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 553
netstat -ano | findstr :553

From another machine

nmap -p 553 -sV <host>
sudo nmap -sU -p 553 <host>
nc -zv <host> 553

Block it in the firewall

sudo ufw deny 553/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 553" -Direction Inbound -LocalPort 553 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 553 used for?

Port 553 is assigned by IANA to pirp (pirp).

Is port 553 TCP or UDP?

Port 553 is registered for TCP and UDP.

Is it safe to open port 553?

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 553 is open?

On Linux run "ss -ltnup 'sport = :553'", on macOS "lsof -nP -i :553", and on Windows "netstat -ano | findstr :553" to see the local process. From another machine, "nmap -p 553 <host>" shows whether it is reachable.

05 Related
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