Port 947: Unassigned — A quiet gap in the port registry

Port 947 has no story to tell. At least not yet.

What This Port Is

Port 947 falls in the well-known ports range (0-1023), the section of port numbers that IANA—the Internet Assigned Numbers Authority—reserves for system services and widely-used protocols. These are the ports that require root privileges to bind on Unix systems, the ones deemed important enough to control centrally.

But port 947 was never assigned. It sits in a block (914-952) that IANA has left unallocated.¹

Why Unassigned Ports Exist

The well-known port range has 1,024 slots. Not all of them are filled. Some numbers were skipped over as protocols evolved. Some were reserved for services that never materialized. Some were simply left open for future use.

Port 947 is one of these gaps—a number without a protocol, a door without a room.

Could Something Be Using It?

Just because IANA hasn't assigned a port doesn't mean nothing ever uses it. Software can bind to any port it wants. A custom application, a piece of malware, or an internal service could theoretically listen on port 947.

To check what's actually using this port on your system:

Linux/macOS:

sudo lsof -i :947
sudo netstat -tulpn | grep :947

Windows:

netstat -ano | findstr :947

If something appears, it's not an official service—it's either custom software you're running or something that shouldn't be there.

The Importance of Empty Space

Unassigned ports matter because they represent flexibility. The Internet's protocol designers couldn't predict every service that would ever need a port number. Leaving gaps means room for future protocols, experimental services, or temporary uses that don't require permanent IANA registration.

Port 947 is one of these spaces—quiet, unassigned, waiting.

Related Ports

The entire block from 914 to 952 is unassigned. All 39 of these ports sit empty in the well-known range, reserved by authority but claimed by no one.