Port 3572: Megaregsvrport — Registered, but Forgotten

What Port 3572 Is

Port 3572 lives in the registered ports range (1024–49151). IANA maintains this range as a directory where organizations and developers can formally claim a port number for a specific service, preventing collisions with other protocols.

In August 2002, someone registered port 3572 under the name megaregsvrport — short, apparently, for "Registration Server Port." ¹

That's where the trail ends.

No RFC was published. No widely deployed software adopted it. No documentation explains what problem this registration server was meant to solve, who built it, or whether it ever ran in production anywhere. The registration sits in the IANA database the way a domain name sits parked — technically claimed, practically empty.

What the Registered Range Means

When you see a port in the 1024–49151 range, it means one of three things:

1. It has an active IANA assignment — a well-known service (PostgreSQL on 5432, Redis on 6379, MySQL on 3306) that the community actually uses
2. It has a forgotten IANA assignment — a port like 3572, registered once and never deployed
3. It has no assignment at all — free for any application to use dynamically or by convention

Port 3572 falls into the second category. The name is registered. The port is not in active use. If you see traffic on 3572, it has nothing to do with "megaregsvrport" — it's something else running on an available port.

What to Do If You See Port 3572 Open

An open port 3572 on your system isn't inherently alarming, but it warrants a look. Something is listening — you just need to find out what.

On Linux or macOS:

# See what process is using port 3572
sudo lsof -i :3572

# Or with ss
ss -tlnp | grep 3572

On Windows:

# Show all listening ports with process IDs
netstat -aon | findstr :3572

# Then look up the PID
tasklist | findstr <PID>

The process name will tell you what you're dealing with. Development servers, local applications, and game clients all pick ports opportunistically — 3572 is available, so something might have landed there.

Why These Placeholder Registrations Exist

The IANA assignment process is intentionally low-friction. An organization submits a request, IANA reviews it, and if there's no conflict, the port gets a name in the registry. There's no requirement to publish an RFC, no enforcement that the service actually ship, no expiration date on the claim.

The result is a registry full of ghosts. Ports registered in the early 2000s for software that never launched, internal tools that never needed the official slot, or products that shipped under a different port number than originally planned.

Port 3572 is one of these. It has a name. It has a registration date. It has no story.