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// Voice & chat

Port 529: IRC-SERV

Port 529 is assigned by IANA to irc-serv (IRC-SERV).

529

How irc-serv works

Voice & chat
callercalleeirc-serv callercalleeirc-serv

Port 529 sets up the call (who calls whom), then the voice travels as a stream of audio packets.

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
Voice & chat
01 Security

Is port 529 dangerous?

We have no specific security note for port 529. Its risk depends on the program actually listening on it. General advice for voice & chat services:

  • Use strong credentials and TLS for signalling.
  • Rate-limit registrations to stop extension scanning and toll fraud.
  • Alert on unexpected chat protocols leaving servers (possible command and control).
02 Registry

IANA registry entries for port 529

ServicePortTransportDescriptionReferenceUpdated
irc-serv 529 TCP, UDP IRC-SERV - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 529, and is it reachable?

Linux

sudo ss -ltnup 'sport = :529'      # process listening on 529
sudo lsof -nP -i :529

macOS

sudo lsof -nP -i :529

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 529 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 529
netstat -ano | findstr :529

From another machine

nmap -p 529 -sV <host>
sudo nmap -sU -p 529 <host>
nc -zv <host> 529

Block it in the firewall

sudo ufw deny 529/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 529" -Direction Inbound -LocalPort 529 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 529 used for?

Port 529 is assigned by IANA to irc-serv (IRC-SERV).

Is port 529 TCP or UDP?

Port 529 is registered for TCP and UDP.

Is it safe to open port 529?

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. Use strong credentials and TLS for signalling.

How do I check if port 529 is open?

On Linux run "ss -ltnup 'sport = :529'", on macOS "lsof -nP -i :529", and on Windows "netstat -ano | findstr :529" to see the local process. From another machine, "nmap -p 529 <host>" shows whether it is reachable.

05 Related

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