Port 569: MS-Rome — The ghost port with no story

Port 569 sits in the IANA registry as "ms-rome" (Microsoft Rome), assigned to both TCP and UDP. There's a contact name—Rudolph Balaz—and an official registration. But that's where the trail goes cold.

What We Know

Port 569 is in the well-known ports range (0-1023), which means it was assigned by IANA for a specific service.¹ These ports are reserved for system or well-known services, the kind that should have RFCs, documentation, and a clear purpose.

MS-Rome has none of that.

What We Don't Know

What did Microsoft Rome do? When was it created? Is it still used anywhere? The IANA registry lists it, port scanning databases know about it, but nobody explains what it is.²³

There's a Microsoft Project Rome—a cross-device experiences platform for Windows—but that's a modern SDK for connected apps and devices.⁴ Whether it has any relationship to the ms-rome port registered decades ago is unclear. The naming is suggestive, but there's no documentation linking them.

The Ghost Port Pattern

Port 569 isn't alone. The Internet's port registry is full of these ghosts—services registered in the 1980s and 1990s that have faded from memory. Someone needed a port number, filed the paperwork with IANA, and got port 569 assigned to "microsoft rome." Then the project ended, or pivoted, or was never released, and the port became a permanent relic.

The registration remains because port numbers aren't recycled. Once assigned, they stay assigned, even if the service dies.

How to Check What's Listening

If you want to see if anything is actually using port 569 on your system:

On Linux/Mac:

sudo lsof -i :569
netstat -an | grep 569

On Windows:

netstat -ano | findstr :569

Chances are, you'll see nothing. Port 569 is assigned, but it's not carrying traffic.

Why This Matters

Unassigned or forgotten ports reveal something about how the Internet works. Port numbers are finite—only 65,535 exist for each protocol. The well-known range (0-1023) is especially limited. When ports are assigned but never used, or used briefly and abandoned, they become archaeological artifacts.

Port 569 has a name. It has an official registration. It belongs to Microsoft. But what it does—or did—is a mystery the Internet has forgotten to document.