Port 183 sits in the well-known ports range (0-1023), officially assigned by IANA. It has a name: OCBinder. It has a date: July 1992. It has a contact person: Jerrilynn Okamura from a company called Ontologic.1 But beyond these registry entries, port 183 has almost no story to tell.
What We Know
Port 183 is assigned to OCBinder for both TCP and UDP protocols.2 The assignment first appeared in RFC 1340, the July 1992 edition of "Assigned Numbers"—the document that tracked all official Internet protocol parameters.3 A companion service called OCServer was assigned to port 184, suggesting these were part of a larger system.
The registration indicates this was intended to be a serious service. Well-known ports below 1024 required IETF Review or IESG Approval—these weren't handed out casually. Someone at Ontologic built something they believed would matter enough to claim a permanent spot in the Internet's addressing system.
What We Don't Know
Almost everything else. What problem did OCBinder solve? What did it bind? Was it ever deployed in production? Did anyone outside Ontologic ever run it? The protocol left no documentation, no surviving implementations, no mention in technical papers, no memory in the network engineering community.
Ontologic itself has vanished. The company isn't remembered in the tech industry's historical record. No acquisitions, no notable products, no archive of what they built. Just a name in an RFC contact list.
The Well-Known Ports Range
Port 183 belongs to the well-known ports range (0-1023), also called system ports. These are administered by IANA and require formal approval for assignment. This range includes the Internet's fundamental protocols: HTTP on port 80, HTTPS on port 443, SSH on port 22, DNS on port 53.
But it also includes dozens of ports like 183—officially assigned to services that never achieved widespread adoption or have since been abandoned. These ghost ports are a reminder that not every protocol becomes infrastructure. Some are experiments that didn't work out, solutions to problems that never materialized, or products from companies that quietly disappeared.
Checking What's Listening
If you want to see if anything is actually using port 183 on your system:
On Linux or macOS:
On Windows:
Most likely, you'll find nothing. Port 183 is probably silent, as it has been for decades.
Why Unassigned and Forgotten Ports Matter
Port 183 tells a different kind of infrastructure story. Not every protocol succeeds. Not every service becomes essential. Not every port assignment turns into something millions depend on.
The IANA registry preserves these assignments anyway. Port 183 will remain assigned to OCBinder indefinitely, even though OCBinder is gone. This permanent reservation means no other service can officially claim port 183, even though nothing is using it.
It's a strange form of digital archaeology—a registry entry that outlived the protocol, the company, and anyone who remembers what it was for. Port 183 exists in name only, a ghost in the machine, officially recognized but functionally forgotten.
Sometimes the most honest thing you can say about a port is: we don't know what this was for, and nobody remembers.
Related Ports
- Port 184 (OCServer) — OCBinder's companion service, equally forgotten
- Port 182 (Unassigned in early RFCs) — The port number before OCBinder
- Port 0-1023 (Well-Known Ports) — The range containing both essential protocols and abandoned experiments
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