Port 498 sits in the well-known ports range (0-1023), officially assigned by the Internet Assigned Numbers Authority to a service called "siam." That's where the certainty ends and the mystery begins.
What We Know
According to IANA's official registry, port 498 is assigned to "siam" for both TCP and UDP.1 The assignee is listed as Philippe Gilbert. There's no RFC. No protocol specification. No widespread documentation. Just an entry in a registry and a name that leads nowhere.
Some sources claim it was used for "remote token-ring administration"—managing Token Ring networks, the LAN technology that dominated in the 1980s and 90s before Ethernet won.2 But even that description is thin, unsourced, and impossible to verify.
The Well-Known Ports Range
Port 498 belongs to the well-known ports (0-1023), the range IANA reserves for standardized services. These are supposed to be the foundational protocols of the Internet: HTTP on 80, HTTPS on 443, SSH on 22. Getting a well-known port assignment meant your protocol mattered—or at least, someone thought it would.
But not every well-known port became well-known. Some protocols never took off. Some served incredibly specific niches. Some were assigned in the early days of the Internet when the process was less formal and the registry less crowded.
Port 498 is one of those. Assigned, official, and essentially invisible.
Why Unassigned and Obscure Ports Matter
The port registry is a historical document as much as a technical one. Every assigned port represents someone's attempt to solve a problem. Port 498 represents a solution to something—Token Ring management, perhaps, or something else entirely—that either worked so well nobody needed to talk about it, or failed so quietly that nobody remembered.
These ghost ports remind us that the Internet isn't just the protocols that won. It's also the protocols that didn't, the ones that served their purpose and faded, the ones assigned in hope and abandoned in practice.
Checking What's Listening
If you want to see if anything is actually using port 498 on your system:
On Linux/macOS:
On Windows:
If something appears, it's either a legacy service, something repurposing the port, or—more likely—nothing at all.
The Mystery Remains
Port 498 exists. It's assigned. It's official. And it's a ghost. No active community, no modern implementations, no clear documentation of what "siam" actually did or why it needed a well-known port.
Maybe it mattered once. Maybe it still serves some forgotten corner of the Internet. Or maybe it's just a reminder that not every door in the Internet's architecture leads somewhere you can see.
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