Port 3480: Plethora — Registered to One Thing, Used for Another

What This Port Is

Port 3480 sits in the registered ports range (1024–49151). These are ports that anyone can formally claim with IANA — the Internet Assigned Numbers Authority — by submitting an application. IANA records the name and intended use, but registration doesn't mean enforcement. Nothing stops other software from using any port it wants, and nothing requires the registered software to actually ship.

Port 3480 illustrates this perfectly.

The Official Registration: Plethora

IANA lists port 3480 under the service name plethora, described as a "Secure Virtual Workspace" — software that lets users access remote applications and desktops over the Internet. The registration exists. The service itself has essentially no documented user base, no RFC, no active community, and no detectable presence on the modern Internet.

This happens more than you'd expect. Companies register ports during development, products pivot or die, and the registration persists in the IANA database long after anyone cares. Plethora is one of hundreds of ghost registrations: officially claimed, practically abandoned.

What Actually Runs Here: Vera Smart Home

The most consistent real-world user of port 3480 is the Vera smart home controller, a home automation hub that uses this port for its local Luup HTTP API. Vera devices listen on port 3480 by default to accept commands from apps and automation software running on the same local network — things like turning lights on, reading sensor states, or triggering scenes.

If you have a Vera hub (or its successor, Ezlo), there's a reasonable chance something is listening on port 3480 in your home right now.

How to Check What's Listening

If you see port 3480 open on a machine and want to know why:

On Linux/macOS:

sudo ss -tlnp | grep 3480
# or
sudo lsof -i :3480

On Windows:

netstat -ano | findstr :3480

The process name in the output will tell you what claimed the port. On a home network, if you see something Vera-related, that's expected. On a server, an unexpected listener on 3480 is worth investigating.

Why Unassigned Ports Matter

The registered range exists to reduce collisions — to give software a designated home so two applications don't fight over the same port. The system works imperfectly. Registrations lapse. Software ignores them. Ports get squatted.

Port 3480 is a small reminder that the port registry is a directory, not a deed. It records intent, not reality. What actually runs on any given port is whatever software decided to listen there, registration or not.