Port 2204: Unassigned — A Registered Port With No Registered Owner

Port 2204 has no officially assigned service. IANA, the organization responsible for port number assignments, lists it as unassigned in the registered port range.¹

That's the complete official record. Everything else depends on your system.

What Range This Port Belongs To

Port 2204 falls in the registered port range: 1024–49151.

Here's how the three ranges break down:

Registered ports don't require a fee or formal approval to use — IANA registration is voluntary. An application can listen on any unassigned port without registering it. Many do.

No Known Unofficial Uses

Unlike some unassigned ports that accumulate unofficial associations over time — through malware signatures, forum posts, or firewall rule documentation — port 2204 has no prominent unofficial uses in public records.

If you're seeing traffic on port 2204, it's specific to your environment: a local application, a custom service, or in some cases, a scan or probe from external hosts.

How to Check What's Listening

On Linux or macOS:

ss -tlnp | grep 2204
# or
lsof -i :2204

On Windows:

netstat -ano | findstr :2204

The output will show the process ID (PID) holding the port. You can look up the process name from there.

With nmap (from another machine):

nmap -p 2204 <target-ip>

This tells you whether the port is open, closed, or filtered by a firewall — not what service is running, but whether anything is listening at all.

Why Unassigned Ports Matter

The registered range has 48,127 slots. IANA has assigned a few thousand of them. The rest — port 2204 among them — are available, unnamed territory.

This isn't a flaw. It's headroom. When a developer builds a new application and needs a port, they pick something unassigned and either register it with IANA or leave it informal. The Internet's port space has always grown this way: informal first, registered later, if ever.

The absence of an assignment doesn't mean the port is unused. It means whatever's using it hasn't asked for a name.