Port 622: Collaborator — The assigned port with no visible service

Port 622 sits in an odd category: officially assigned, but practically invisible.

What the Registry Says

According to IANA (Internet Assigned Numbers Authority), port 622 is assigned to a service called "Collaborator" for both TCP and UDP protocols.¹ That's where the trail ends. No RFC describes it. No documentation explains what it does. No active implementations appear in the wild.

The port exists in the registry, but the service itself seems to have vanished—if it ever existed at all.

The Well-Known Range (0-1023)

Port 622 falls within the well-known ports range (0-1023), which means:

• Only IANA can make assignments in this range
• The port was allocated through some formal process
• Someone, at some point, requested this number for a specific purpose
• That purpose has been lost to time

Well-known ports are supposed to be for fundamental Internet services—DNS at 53, HTTP at 80, HTTPS at 443. Port 622's "Collaborator" sits among them, a name without a protocol.

Why This Happens

The port registry is full of these ghosts. Services get assigned port numbers during development, then:

• The project gets abandoned before release
• The company goes out of business
• The protocol gets superseded by something better
• Nobody remembers to update the registry

The assignment remains. The service doesn't.

What Might Be Listening

Just because port 622 has no official active service doesn't mean nothing uses it:

• Custom applications might choose any available port
• Malware sometimes camps on obscure assigned ports
• Private networks might repurpose it for internal tools

To check what's actually listening on port 622 on your system:

Linux/Mac:

sudo lsof -i :622
sudo netstat -tulpn | grep :622

Windows:

netstat -ano | findstr :622

If something answers, it's not the official "Collaborator"—it's something else entirely.

The Value of Empty Assignments

These ghost assignments serve a purpose: they prevent ambiguity. Because port 622 is officially assigned (even to a dead service), no new protocol can claim it without going through IANA's process. This prevents two different services from accidentally choosing the same port and creating conflicts.

The registry isn't just a list of active services. It's a historical record and a reservation system, protecting the port number space from chaos.