Port 3402: FXa Engine Network Port — A Name Without a Story

What Port 3402 Is

Port 3402 sits in the registered port range (1024–49151). These ports are not reserved by the operating system the way well-known ports (0–1023) are, but they are tracked by IANA, the organization that maintains the global registry of port assignments.

IANA records port 3402 as assigned, for both TCP and UDP, to a service called "FXa Engine Network Port" (service name: fxaengine-net), registered in February 2002 by someone named Lucas Alonso.¹

That is the complete record.

The Ghost Assignment

There is no public RFC for FXa Engine. No documentation. No surviving product page. No forum posts asking for help with it. Whatever FXa Engine was — a game engine, a rendering system, a financial tool, something else entirely — it registered a port with IANA in 2002 and then disappeared from the historical record.

This happens. The registered port range is populated partly by software that once mattered to someone, registered a port during active development, and then faded. The name remains in the registry. The software does not.

If you are seeing traffic on port 3402, it is almost certainly not FXa Engine. It is more likely a custom application, development tooling, or something configured deliberately to use this port precisely because it is obscure and unlikely to conflict with anything.

What It Means for You

If port 3402 shows up in your network scans or firewall logs, treat it the same way you would any unexpected traffic: find out what is actually listening before deciding whether to allow or block it.

# On Linux/macOS — see what process is listening on 3402
sudo ss -tlnp | grep 3402
sudo lsof -i :3402

# On Windows
netstat -ano | findstr :3402

If nothing is listening, the traffic is inbound and probably noise — automated scanners probe obscure registered ports constantly, looking for anything that responds. If something is listening, that process name will tell you more than the port number ever could.

Why Unassigned-in-Practice Ports Matter

The registered port range has over 48,000 slots. Many are formally assigned to products that no longer exist. Many more are genuinely unassigned. Developers reach into this range when they need a port for a new service, a development server, or internal tooling — and they usually pick something that looks quiet.

Port 3402 is quiet. Whatever FXa Engine was, it is not competing for this port anymore.