What Port 1675 Is
Port 1675 sits in the registered port range (1024-49151). These are ports that individuals and organizations can formally claim through IANA, the body that coordinates Internet address space and port assignments.
According to the IANA Service Name and Transport Protocol Port Number Registry, port 1675 is assigned to a service called pdp, registered by Gary Morton on behalf of Pacific Data Products.1 That entry covers both TCP and UDP.
That's where the trail ends.
The Problem with This Registration
Pacific Data Products appears to be a defunct company. No active documentation for its protocol exists. No RFC was ever published. No modern software is known to use this port for its registered purpose.
The IANA registry is not automatically pruned. When a company registers a port and then disappears, the registration stays. Port 1675 is one of hundreds of registered ports in this situation: technically claimed, practically abandoned.
In real-world network traffic, you're unlikely to encounter anything legitimately using port 1675 for "Pacific Data Products." If something is listening on this port on your system, it's almost certainly a different application that chose this number informally, or something worth investigating.
What the Registered Port Range Means
The registered range (1024-49151) works differently than the well-known ports below 1024. Any process can bind to a registered port without elevated privileges. This makes the range useful for application servers, databases, and custom services, but it also means traffic on any given port in this range could be almost anything.
Unlike ports below 1024, which are tightly controlled and mapped to foundational protocols (HTTP on 80, SSH on 22, DNS on 53), registered ports are more loosely governed. Many are actively used. Some, like 1675, are registered to things that no longer exist.
How to Check What's Using This Port
If you see port 1675 active on a machine, these commands will tell you what's listening:
Linux/macOS:
Windows:
The output will show you the process ID. From there, you can look up the process name in Task Manager or with ps on Unix systems.
Why Ghost Registrations Exist
Port registrations were designed to be permanent claims. The logic made sense: if a company builds a product around a specific port, other services shouldn't collide with it. But IANA has no mechanism for reclaiming ports when registrants disappear.
The result is a registry that's partly a living directory and partly an archaeological record. Port 1675 is the latter. Gary Morton filed the paperwork. Pacific Data Products got their number. Whatever they built, it's gone now.
The port itself remains, patient and unclaimed, in the middle of a 48,000-port range that contains everything from active enterprise software to similar monuments to businesses that didn't make it.
Apakah halaman ini membantu?