Port 529: IRC-SERV — The official port nobody used

Port 529 carries a strange distinction: it's officially assigned by IANA for Internet Relay Chat server communication, yet it was almost never used for that purpose. The IRC community looked at the official port assignments and chose a different path.

What Runs Here (Officially)

Port 529 is designated for irc-serv—IRC server-to-server communication protocol.¹ It's one of three official IRC ports:

• Port 194: Standard IRC client-server communication
• Port 529: IRC server-to-server communication
• Port 994: Secure IRC over TLS/SSL

All three were assigned in the well-known port range (0-1023), which seemed reasonable at the time. The problem was what that range actually meant.

The Root Privilege Problem

Ports 0-1023 are privileged ports on Unix-like systems. Opening them requires superuser (root) access. This means any IRC daemon listening on port 529 would need to run with root privileges—or at least start with them before dropping to a less privileged user.

For IRC operators in the 1990s, this was unacceptable. Running network-facing chat software with root privileges was a security nightmare waiting to happen. One vulnerability in the IRC daemon and an attacker would own the entire system.

The IRC community had a choice: use the official ports and risk their systems, or ignore the assignments and choose safer alternatives.

What Actually Happened

IRC operators collectively abandoned the official ports. Instead, they standardized on ports 6665-6669, with 6667 becoming the de facto default.² These ports sit well above the privileged range. Any user can open them without superuser access.

This wasn't a small deviation—it was a complete rejection of the official standard. When RFC 1459 documented the IRC protocol in 1993,³ the community was already using the higher ports. The IANA assignments became historical footnotes.

Why This Matters

Port 529 represents a fascinating moment in Internet history: a community choosing practical security over official designation. The IRC operators saw a problem with the assigned ports and solved it themselves. They didn't wait for IANA to reassign the ports. They didn't petition for changes. They just moved.

This is the Internet working as designed—distributed, pragmatic, solving problems locally rather than waiting for central authority to catch up.

What You'll Find on Port 529 Today

Almost nothing. If you scan for port 529 today, you'll rarely find it open. When you do, it's more likely a misconfigured system or someone running historical IRC software than actual server-to-server communication.

To check what's listening on port 529 on your system:

# Linux/macOS
sudo lsof -i :529
sudo netstat -tulpn | grep :529

# Windows  
netstat -ano | findstr :529

Most likely, you'll find nothing. Port 529 is assigned but unused—a ghost port, officially designated for a service that chose to live elsewhere.

The Current State of IRC

Modern IRC still runs primarily on ports 6665-6669 for standard connections and port 6697 for TLS/SSL encrypted connections.⁴ The official assignments—194, 529, 994—remain in the IANA registry, but they're artifacts of a decision that the community overruled through practice.

Related Ports

• Port 194 — IRC (the other abandoned official port)
• Port 994 — IRCS (secure IRC, also mostly unused)
• Port 6667 — De facto standard IRC port (what everyone actually uses)
• Port 6697 — IRC over TLS (the real secure IRC port)