Port 2874: DX Message Base Transport Protocol — Registered and Forgotten

What This Port Is

Port 2874 is officially assigned by IANA to the DX Message Base Transport Protocol, service name dxmessagebase1. Both TCP and UDP are registered. Its sibling, port 2875 (dxmessagebase2), is assigned to the same protocol family.

That's essentially everything the official record says. No RFC. No public specification. No known active implementations.

What "DX Message Base" Suggests

"DX" is shorthand in amateur radio for distant stations — the thrill of making contact with someone far away. DX clusters and DX message boards are real things in the ham radio world: systems where operators spot and share rare contacts in near real time.

The name suggests port 2874 was intended as a transport layer for one of these amateur radio messaging systems, likely a packet radio BBS variant that wanted a permanent TCP port for IP-based communication. Someone filed the paperwork with IANA. Then, as best anyone can tell, not much else happened.

What the Registry Actually Means

The IANA port registry in the registered range (1024–49151) works on an application basis. Anyone can request an assignment. The bar is not "prove this protocol is widely used." The bar is closer to "fill out the form and demonstrate a plausible use case."

The result is a registry that contains thousands of ports like this one: legitimately assigned, nearly undocumented, and rarely if ever observed in the wild. They're not fake — they just didn't become real in any meaningful sense.

Port 2874 lives in good company. Most of the registered port space looks like this: names without implementations, protocols that never shipped, reservations that were never built on.

What to Do If You See This Port Open

If you find port 2874 open on a system, it almost certainly isn't DX Message Base Transport Protocol. Unknown registered ports showing up in scans usually mean one of three things: a custom internal application chose this port arbitrarily, a development service is running, or something misconfigured is listening where it shouldn't be.

Check what's actually there:

# On Linux/macOS — show what process owns port 2874
sudo lsof -i :2874
sudo ss -tlnp | grep 2874

# On Windows
netstat -ano | findstr :2874

The process name will tell you more than the port number ever could.

Related Ports

• 2875 — dxmessagebase2, the registered sibling port for the same protocol family