Port 3340: anet-m — A Registered Port Nobody Uses

What Port 3340 Is

Port 3340 sits in the registered port range (1024–49151), which means it's above the well-known system ports but below the ephemeral ports your OS assigns for outgoing connections.

IANA lists port 3340 as:

It was registered by Michael Friedman, whose contact address was at @worldnet.att.net — AT&T's consumer Internet service, which shut down in 2002. ¹

The anet Cluster

Port 3340 isn't alone. It's part of a block of four consecutive ports registered together:

The suffixes — b, l, m, h — likely stood for basic, low, medium, high, different tiers or data streams within whatever system "OMF" was. The connection to DirecTV data catalogs suggests this may have been a satellite or broadcast data management system from the late 1990s. Whatever it was, it didn't survive into the modern era.

What "Registered" Actually Means Here

A port being registered with IANA doesn't mean software is running on it. It means someone filed paperwork at some point and IANA noted it. Registration is not enforcement — any software can use any port. The IANA registry is a coordination mechanism, not a lock.

Port 3340 today is effectively unoccupied. If you see something listening on it, it's not anet-m. It's whatever you or someone else put there.

What's Actually on Port 3340

Nothing, by default. But if you want to check your own machine:

Linux/macOS:

ss -tlnp | grep 3340
# or
lsof -i :3340

Windows:

netstat -ano | findstr :3340

If something shows up, the process ID will tell you what it is. On Linux, lsof will show you the executable path directly.

Why These Gaps Exist

The registered port range has 48,128 ports. IANA has formally assigned only a fraction of them. The rest — including most ports near 3340 — are either unused, informally occupied by software that never bothered to register, or registered by projects that came and went.

Port 3340 is the third kind: once claimed, now unclaimed in any practical sense. The Internet is full of these quiet addresses, reserved in name only, waiting for someone to actually use them.