Port 1380: Telesis Network License Manager — A ghost from the licensing wars

Port 1380 sits in the registered ports range (1024-49151), officially assigned to a service called "Telesis Network License Manager" (telesis-licman). Both TCP and UDP port 1380 were registered by Karl Schendel, Jr. for this purpose.¹

The service itself has vanished. No website. No documentation. No trace beyond the IANA registry entry.

What Was a Network License Manager?

In the 1990s, commercial software was expensive. A single license for engineering software, CAD tools, or professional applications could cost thousands of dollars. Companies needed a way to share these expensive licenses across their workforce without buying a copy for every employee.

The solution: floating licenses. A central license server would manage a pool of licenses. When someone needed to run the software, their computer would contact the license server over the network and request permission. If a license was available, the server would grant it. When the user closed the application, the license returned to the pool for someone else to use.²

This is what Telesis Network License Manager did. Port 1380 was the door employees' computers knocked on to ask "Can I use AutoCAD right now?"

The Licensing Wars

The 1990s saw competing license management systems—FLEXlm (developed in 1988), Sentinel, and others.³ Each vendor needed a port number for their license server. Telesis registered port 1380 for theirs.

Most of these systems are gone now. FLEXlm survived and evolved into FlexNet Publisher, still used by companies like Autodesk and COMSOL. But Telesis? It disappeared.

What Runs on Port 1380 Today?

Nothing, usually. The registered service is defunct. The company appears to be gone. If you see port 1380 open on a modern network, it's either:

• Legacy software from the 1990s still running (rare)
• A custom application repurposing the port number
• A misconfiguration
• Something worth investigating

To check what's listening on port 1380:

# On Linux/Mac
sudo lsof -i :1380
netstat -an | grep 1380

# On Windows
netstat -ano | findstr :1380

If something is listening and you don't recognize it, find out why. Port 1380's official purpose is dead. Anything using it now is doing so unofficially.

Why Unassigned Ports Matter

Port 1380 is technically assigned, but functionally abandoned. This happens more than you'd think. Software companies register ports, then disappear. Services become obsolete. The IANA registry fills with ghosts.

The registered ports range (1024-49151) contains thousands of these—port numbers claimed decades ago for purposes that no longer exist. They're not harmful. They're just empty rooms in the Internet's address space.

But they remind us: the port system isn't just about what's running now. It's an archaeological record of every network service anyone ever thought important enough to register. Port 1380 is a fragment of the 1990s licensing wars, preserved in a registry nobody reads.