Port 3467: RCST — The Most Unexpected Entry in the IANA Registry

What Port 3467 Is

Port 3467 falls in the registered port range (1024–49151). These ports are managed by IANA, which maintains a registry where individuals and organizations can submit an application to claim a service name and port number. Unlike the well-known ports (0–1023), registered ports don't require IETF review — just an application and a contact address.

Port 3467 is registered to the service name RCST, submitted by Kit Sturgeon with a contact at remotecontrolsextoys.com. IANA recorded it for both TCP and UDP. No RFC was ever filed. No public protocol specification exists. The port was claimed, the paperwork was done, and that appears to be where the story ends — at least publicly.

What the Registered Range Means

The registered port range exists so that applications have a reasonably stable, semi-official home. If your software consistently uses port 3467, registering it prevents collisions — another application knowing that port is "spoken for."

But registration doesn't mean enforcement. Nothing stops any application from using any registered port. It's a coordination mechanism, not a lock. The registry is a shared agreement, and plenty of registered ports see zero real-world traffic while others are quietly repurposed by software that never checked the list.

What Might Actually Be on Port 3467

If you see traffic on port 3467 in the wild, it's almost certainly not RCST. More likely candidates:

• Custom application traffic — internal tools, game servers, or development services that chose this port arbitrarily
• Malware — some port scanners flag 3467 as historically associated with backdoors and remote access trojans, though no specific, well-documented family claims it definitively¹
• IoT or smart device protocols — devices that pick registered-range ports for local communication

How to Check What's Listening

# On macOS or Linux — show what's using port 3467
sudo lsof -i :3467

# Or with ss (Linux)
ss -tlnp sport = :3467

# On Windows
netstat -ano | findstr :3467

If something is listening, the process name will tell you more than the port number ever could.

Why Unassigned (and Barely Assigned) Ports Matter

The 65,535 available ports are not infinite. Well-known ports (0–1023) are tightly controlled. The registered range is looser — a first-come, first-served system that reflects who bothered to file. Most of the registered range is either empty or sparsely documented.

Port 3467 sits in that territory: technically claimed, essentially undocumented, and almost certainly unused for its registered purpose. It's a reminder that the port registry is less a precise map and more a historical artifact — a record of who showed up.