Port 3662: pserver — A Name Without a Story

What Range This Port Belongs To

Port 3662 sits in the registered ports range (1024–49151). These ports are managed by IANA: anyone can apply to register a service name, and IANA records it on a first-come, first-served basis. Registration doesn't mean the port is widely used. It means someone once filed the paperwork.

Unlike well-known ports (0–1023), registered ports require no special operating system privileges to open. Any application running as a normal user can bind to port 3662.

The Nominal Assignment

IANA records port 3662 as assigned to "pserver" on both TCP and UDP, registered in January 2003.¹

This creates immediate confusion, because "pserver" is also the name of the authentication mechanism used by CVS (Concurrent Versions System) — the version control system that predated Git. CVS's pserver has lived at port 2401 since the 1990s and is well-documented.²

The "pserver" registered at 3662 is different, but there's no public documentation describing what it was intended to do, no known software that uses it, and no RFC defining it. The registration exists; the protocol doesn't appear to.

In Practice

If you find something listening on port 3662, the IANA registration tells you nothing useful about what it is. It's more likely to be:

• A custom application that picked an out-of-the-way port number
• A game server or peer-to-peer client using the port opportunistically
• Malware (port scanners flag unfamiliar open ports for exactly this reason)

The registration is a historical artifact. Treat the port as functionally unassigned.

How to Check What's Listening

macOS / Linux:

lsof -i :3662

Linux (alternative):

ss -tlnp | grep 3662

Windows:

netstat -ano | findstr :3662

These commands show the process ID and name of whatever has the port open. If nothing returns, nothing is listening.

Why Unassigned Ports Matter

65,535 ports sounds like a lot until you consider how many applications exist. Registered ports create a shared map — when a service wants a stable, known address, it registers a port so that firewalls and administrators can make consistent decisions.

But the map has gaps. Port 3662 is one of them: nominally claimed, practically empty. These gaps are where custom applications park, where attackers hide, and where network monitoring earns its keep.

An open port you didn't put there is a question worth answering.