Port 1428 is officially registered with IANA for the Informatik License Manager (informatik-lm), a software licensing system that verified and managed software licenses across networks.12 The port operates on both TCP and UDP protocols.
Here's the strange reality: the company behind this service, Informatik Inc., closed in February 2023.3 Port 1428 remains registered in IANA's official port registry, but the software it was designed to serve no longer exists as an active product.
What License Managers Do
Software license managers are network services that control how many users can run a particular piece of software at once. When you launch a licensed application, it contacts the license server on its designated port—in this case, port 1428—and asks "Can I run?" The server checks how many licenses are available and either grants permission or tells you to wait.4
This model was especially common with expensive engineering and design software where companies owned a limited number of licenses but had more users who needed occasional access.
The Registered Port Range
Port 1428 sits in the registered ports range (1024-49151). These ports are assigned by IANA for specific services upon application, but unlike well-known ports (0-1023), they don't require administrative privileges to use.5
Companies or developers can request registration for a specific port when building a service that needs a consistent port number across installations. Informatik did this when they created their license manager, ensuring that every deployment would use port 1428 by default.
A Port That Outlived Its Purpose
This is what happens in the port system: services come and go, companies close, software becomes obsolete—but port registrations remain. Port 1428 is technically still assigned to informatik-lm in the official registry, even though the company that registered it no longer exists.
Some old installations might still be running somewhere, quietly checking licenses on port 1428 for software that will never be updated. But mostly, this port sits unused—a reserved number in a database, waiting for a service that won't return.
Security Considerations
If you see port 1428 open on your network and you're not running Informatik software (which is increasingly unlikely given the company's closure), investigate. While the port itself isn't inherently dangerous, unexpected open ports can indicate:
- Legacy software that should be decommissioned
- Misconfigurations where software is listening on the wrong port
- Rarely, malicious software using registered ports to appear legitimate6
Checking Port 1428
To see if anything is listening on port 1428:
Linux/Mac:
Windows:
Most modern networks won't have anything running on this port anymore.
Why This Port Matters
Port 1428 tells a story about the Internet's infrastructure. Ports are registered with the expectation that services will run forever, but nothing runs forever. Companies close. Software becomes obsolete. Yet the port registrations remain—archaeology in a database.
Thousands of registered ports have similar stories. They were meaningful once. Someone filled out the IANA application form. Someone designed a protocol. Someone built software that needed this specific number. And then the world moved on.
Port 1428 is a reminder that the Internet we use today is built on layers of history—including the history of things that no longer exist.
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