Port 2112: Idonix MetaNet — A Registered Ghost

What Port 2112 Is

Port 2112 lives in the registered port range — numbers 1024 through 49151, where IANA tracks assignments for known services. Unlike the well-known ports below 1024 (where HTTP, SSH, and DNS live), registered ports don't require root privileges to bind. Any application can use them.

IANA's registry lists port 2112 as assigned to Idonix MetaNet, a networking service from a company called Idonix. Both TCP and UDP are registered. The registration is real. The company, however, is not findable. Idonix appears to have dissolved, taking its MetaNet service with it.¹

This makes port 2112 a ghost port: formally claimed, practically available. No active software is known to use it for its registered purpose.

Unofficial Uses

Port 2112 has appeared in a few scattered contexts:

• Some older documentation lists it alongside "KIP" (Kerberos over IP) and "POS Partner 2000" (a point-of-sale system), though neither is an authoritative assignment.
• Security scanners occasionally flag it during probes of the registered port range — not because it's dangerous, but because any open port in this range warrants a look if you didn't open it yourself.
• Developers sometimes choose it deliberately for internal services, either for the Round Number Appeal (2112 is memorable) or, let's be honest, because of Rush.

The Number

Rush released 2112 in 1976. The title track runs 20 minutes and describes a dystopian future where the Priests of the Temples of Syrinx control all music and suppress individual creativity. It became one of the defining albums of progressive rock.²

This has nothing to do with networking. But it explains why, if you see port 2112 hardcoded somewhere in a config file, there's a non-trivial chance the person who wrote it owns the vinyl.

How to Check What's Listening on Port 2112

If you see port 2112 active on a system, these commands will tell you what's using it:

macOS / Linux:

# Show what process is listening on port 2112
lsof -i :2112

# Or with ss (Linux)
ss -tlnp | grep 2112

Windows:

netstat -ano | findstr :2112

The output will include the process ID (PID). Cross-reference it with your process list to identify the application.

If something is listening on port 2112 and you didn't put it there, that's worth investigating — not because 2112 is a known attack vector, but because unexpected open ports always are.

Why Unassigned-in-Practice Ports Matter

The registered port range exists so services can stake a claim, coordinate with other software, and avoid collisions. When a company registers a port and then disappears, that port enters a gray zone: technically claimed, functionally available, occasionally squatted on by software that assumes no one's home.

Most of the 48,128 registered ports are like this. IANA's registry is a historical record as much as a live directory. Real coordination happens at the application layer — your software uses a port, you document it, and you hope no one else is already there.

Port 2112 is unclaimed enough that you can use it without practical conflict. Just know that IANA still has Idonix MetaNet's name on the deed.