Port 1108: ratio-adp — The ghost in the registry

Port 1108 is officially registered with IANA for a service called "ratio-adp" on both TCP and UDP.¹ That's where the certainty ends.

The Mystery Protocol

Search for documentation about ratio-adp and you'll find almost nothing. No RFC. No protocol specification. No known implementations. Just the registration itself—a name in the official port registry with no explanation of what it does, who created it, or why it exists.

This happens more often than you'd think. Someone registers a port for a protocol they're developing, the project dies or goes private, and all that remains is the registration. Port 1108 is one of these ghosts—officially claimed but effectively empty.

What Range This Port Belongs To

Port 1108 sits in the registered ports range (1024-49151). These ports are registered with IANA for specific services, but unlike well-known ports (0-1023), they don't require special privileges to use.²

The registered ports range is where most modern network services live. When someone develops a new network protocol or service, they can request a port number from IANA. Once granted, that port becomes the official home for that service—at least in theory.

In practice, not all registered ports see active use. Some protocols never gain traction. Some companies register ports for internal services that never become public. Some registrations, like ratio-adp, simply fade into obscurity.

Why Unassigned (or Forgotten) Ports Matter

The port numbering system only works if it's managed. Without IANA maintaining the registry, different services would claim the same ports and collide. Even mysterious registrations like port 1108 serve a purpose: they prevent future conflicts.

If ratio-adp ever resurfaces—or if someone else wants to use port 1108—the registry shows it's claimed. That's better than having two different services unknowingly using the same port number.

How to Check What's Listening

Even though ratio-adp has no known public implementation, something could still be using port 1108 on your system. Here's how to check:

On Linux or macOS:

sudo lsof -i :1108
# or
sudo netstat -tulpn | grep 1108

On Windows:

netstat -ano | findstr :1108

If something appears, it's either a private implementation of ratio-adp, or more likely, a different service using this port unofficially.

The Silence

Port 1108 exists in the registry. Its name is ratio-adp. Beyond that, there's only silence. No specifications. No implementations anyone can find. Just a number, a name, and the possibility that somewhere, in some forgotten network, ratio-adp is still running.