Port 3111: wsynch — The Registered Port That Never Arrived

Port 3111 sits in the registered ports range (1024–49151), the middle tier of the port numbering system. These ports are neither the well-known workhorses below 1024 (HTTP, SSH, DNS) nor the free-for-all ephemeral ports above 49151. They are supposed to be claimed, named, and used for something specific.

Port 3111 was claimed. It was named. The "using" part never happened.

What IANA Says

The Internet Assigned Numbers Authority (IANA) lists port 3111 as assigned to wsynch — short for "Web Synchronous Services" — on both TCP and UDP.¹ That is the entirety of the official record. There is no RFC defining the protocol, no specification, no reference implementation, and no documented deployment. The registration exists; the protocol does not.

This is more common than it sounds. The registered ports range contains thousands of entries from organizations and developers who claimed a port number, perhaps with genuine intent, and then moved on. The name stays in the registry indefinitely.

What Actually Uses Port 3111

In practice, port 3111 appears occasionally in gaming network configurations. The port range 3074–3174 is sometimes listed for Rainbow Six Vegas by router configuration guides.² This is informal, not standardized, and the game will use whatever port is available.

Beyond that, port 3111 has no consistent real-world use. If you see traffic on port 3111, it is almost certainly application-specific to whatever software is running on that machine.

Checking What Is Listening on This Port

To see if anything on your system is bound to port 3111:

macOS / Linux:

lsof -i :3111

Linux alternative:

ss -tlnp | grep 3111

Windows:

netstat -ano | findstr :3111

If nothing is listening, the port is idle. If something is listening, the process name will tell you what claimed it.

Why This Port Exists in the Registry

The registered ports range exists so that software developers can claim a known, consistent port number for their applications. The idea is to prevent two unrelated programs from defaulting to the same port and colliding. To get a registration, you submit a request to IANA with a service name and description.³

What the system cannot prevent is abandonment. A port gets registered, the project stalls or pivots, and the number stays reserved. Port 3111 is not unique in this regard. It is one entry in a long list of names that outlasted their purpose.

The port is harmless. If your application needs a port and 3111 happens to be free, it can use it. The wsynch registration has no active claimant to object.