Port 3504: IronStorm — The Port That Outlived Its Game

What This Port Does

Port 3504 is registered with IANA as ironstorm, assigned to the multiplayer server component of Iron Storm, a first-person shooter released in 2002 by French developer 4X Studios and published by Wanadoo. The game used ports 3504 and 3505 (TCP and UDP) for its multiplayer functionality, both for in-game hosted servers and dedicated servers.¹

The game is no longer in active multiplayer use. Port 3504 is, in practice, unoccupied — but not unregistered.

The Game Behind the Port

Iron Storm was an alternate-history FPS set in 1964, in a world where World War I had never ended — now in its 50th year. You played an Allied soldier tasked with stopping the Russo-Mongolian Empire from developing nuclear weapons. It was a strange, ambitious game that arrived quietly and departed the same way.²

It has since appeared on Steam and GOG, and a small community occasionally revives its multiplayer servers. If you find port 3504 open on a machine today, someone is almost certainly running an Iron Storm dedicated server — or something entirely unrelated that chose the port arbitrarily.³

What "Registered" Means Here

Port 3504 falls in the registered ports range (1024–49151). These ports are not reserved for exclusive use — any application can use them. But IANA maintains a registry of assignments so that software authors can request a consistent, documented home for their protocols.⁴

Registration is permanent. IANA does not reclaim ports when software dies. So port 3504 belongs to IronStorm on paper, indefinitely, even though no IANA-enforced rule prevents anything else from using it.

This is why you'll find ports assigned to games from the early 2000s, protocols from companies that no longer exist, and services nobody has used in a decade. The registry is a historical record as much as a technical one.

Checking What's on This Port

If you want to see whether anything is listening on port 3504 on your machine:

# macOS / Linux
lsof -i :3504

# Windows
netstat -ano | findstr :3504

# Quick remote check (requires nmap)
nmap -p 3504 <host>

On a typical machine, nothing will be listening. If something is, check the process name — it's almost certainly not an Iron Storm server.

Related Ports

• Port 3505 — IronStorm's companion port, used alongside 3504 for multiplayer¹
• Ports 1024–49151 — The full registered ports range, where IANA assignments live alongside countless unofficial uses