What Range This Port Belongs To
Port 2584 sits in the registered ports range: 1024 through 49151.
This range is governed by IANA (the Internet Assigned Numbers Authority), which maintains a registry of port assignments. Unlike the well-known ports (0-1023), which require IANA approval and are reserved for major protocols, registered ports are available to any software vendor who asks. The barrier to entry is low: submit a request, provide a contact name and email, and IANA assigns the port. No ongoing proof of active use required.
The registered range is where most application-level services live — databases, game servers, enterprise software, and countless proprietary protocols that never made it into widespread use.
The Official Assignment: cyaserv
Port 2584 is technically assigned. IANA's registry lists it as cyaserv, registered by Morgan Jones at Cya Solutions, with a contact email at @cyasolutions.com.
That domain resolves to nothing. The company is not findable. The service has no documentation, no RFC, no open-source implementation, and no apparent presence in the wild. The assignment exists in the registry as a relic — a port number claimed at some point in the past by a company or individual who has since disappeared.
This is not unusual. The registered port range is littered with dead registrations: services for companies that shuttered, software that was never released, and protocols that never left internal use. IANA doesn't automatically reclaim ports when their registrants go dark.
In Practice: Unoccupied
Because cyaserv left no documentation and has no known implementations, port 2584 functions as an unassigned port for all practical purposes. You won't find it in firewall rule templates, vulnerability scanners, or network documentation.
If you see traffic on port 2584, it almost certainly isn't cyaserv. It could be:
- Legitimate custom software that chose an obscure port to avoid conflicts
- Malware or remote access tools using non-standard ports to avoid detection
- Port scanners sweeping the registered range
Some security databases have historically flagged 2584 as associated with certain Trojan activity — the standard fate of obscure unoccupied ports, which are attractive to malware authors for exactly the same reason they're attractive to anyone: nobody is watching.1
How to Check What's Listening on This Port
On Linux/macOS:
On Windows:
Then match the process ID (PID) against Task Manager or Get-Process -Id <PID> in PowerShell.
If something is listening on 2584 and you don't know what it is, that's worth investigating. No widely-used legitimate service should be there.
Why Ghost Registrations Matter
The registered port range contains tens of thousands of entries. Many are active and well-documented. Many others are cyaserv — names attached to services no one can find, from companies that no longer exist, maintained in the registry indefinitely because IANA has no expiration mechanism for port assignments.
This matters for two reasons. First, it obscures the true availability of port numbers — the range looks occupied when it isn't. Second, it creates a gray zone that's difficult to reason about: seeing "cyaserv" in a port listing provides false comfort that the traffic is legitimate.
The honest answer when you encounter port 2584 is the same as for any obscure port: look at what's actually running, not at what the registry says it should be.
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