Port 3711: EBD Server 2 — A Ghost in the Registry

What Port 3711 Is

Port 3711 sits in the registered ports range (1024-49151). These ports are not owned or protected by IANA the way well-known ports (0-1023) are — any process on your system can open them without special privileges. But they are listed. Organizations and developers can file a claim with IANA to associate their product with a specific number, and IANA records it.

Port 3711's entry: EBD Server 2. Filed February 2003. TCP and UDP.

That's all IANA has. No RFC. No documentation. No website that still resolves.¹

What "EBD Server 2" Was

Unknown. The name suggests a second version of something called an EBD Server — possibly an enterprise database product, a network device backend, or any number of things that were being built and named in 2003. Whatever it was, it didn't survive long enough to leave a paper trail the Internet has preserved.

This is not unusual. The registered port space filled up quickly during the late 1990s and early 2000s as companies claimed numbers for products they were building or planning to build. Many of those products shipped, failed, and were discontinued. Their IANA entries remain — quiet reservations for services that no longer exist.

Port 3711 is one of those entries. A reserved seat for a guest who never showed up, or showed up and left.

No Known Unofficial Uses

No documented malware, no scanning campaigns, no community software projects have staked a claim here. If something is running on port 3711 on your machine, it's not because the port has an established unofficial purpose — it's because some software on your system chose it, intentionally or arbitrarily.

How to Check What's Listening

If you see activity on port 3711 and want to know why:

macOS / Linux:

# Show what process is listening on port 3711
lsof -i :3711

# Or with netstat
netstat -tulpn | grep 3711

Windows:

netstat -ano | findstr :3711

The output will give you a process ID (PID). On macOS/Linux, lsof shows the process name directly. On Windows, look up the PID in Task Manager or with tasklist | findstr <PID>.

Why Ghost Registrations Matter

The registered port space exists to reduce collisions — so two different applications don't accidentally pick the same number and conflict on the same machine. The system works when people register ports for real, maintained services.

When registrations become orphaned, the port number occupies conceptual space without serving anyone. It's not reserved in any enforceable sense — anything can use port 3711 — but it sits in the official list, sometimes misleading people who look it up hoping for clarity.

Port 3711 offers an honest lesson about infrastructure: registries are maintained by humans, and humans move on. The Internet's bookkeeping outlasts the things it was meant to track.