Port 364 sits in the well-known port range (0-1023), officially assigned by IANA to a service called "Aurora CMGR"—Aurora Connection Manager.1 Both TCP and UDP protocols are registered to this service. The assignment was made to Philip Budne, whose name appears in IANA's records but whose work has left minimal trace in the documented history of the Internet.
That's all we really know.
What We Don't Know
Search the Internet for Aurora CMGR and you'll find mostly empty references—port databases that dutifully list the assignment, security scanners that note the port number, and nothing else. No RFC. No product documentation. No archived websites explaining what problem this connection manager was meant to solve or what systems used it.
The service appears to have existed, claimed its port number, and then vanished. Or perhaps it never gained widespread adoption. The registry doesn't distinguish between protocols that shaped the Internet and protocols that barely shipped.
The Well-Known Port Range
Port 364 belongs to the well-known ports (0-1023), the range IANA reserves for services deemed important enough for special treatment. On Unix-like systems, binding to these ports requires root privileges. The restriction exists because these ports were meant for fundamental services—the infrastructure everyone depends on.
But not every well-known port lives up to its designation. Some, like port 364, are historical artifacts. The registry is filled with assignments to services that no longer exist, companies that have closed, protocols that were superseded before they shipped.
Why Reserved Ports Matter Anyway
Even though Aurora CMGR appears defunct, its port number remains assigned. IANA doesn't reclaim port numbers easily. The registry is meant to prevent conflicts—if two services claim the same port, neither can coexist on the same system. So ports stay assigned even after their original purpose disappears.
This creates a strange permanence. Port 364 will likely remain reserved for Aurora CMGR forever, a memorial to something that barely existed, taking up space in a range where numbers are genuinely scarce.
Checking What's Actually Listening
If you want to see what's using port 364 on your system:
On Linux or macOS:
On Windows:
Chances are, nothing is listening. But if something is, it's worth investigating—it's unlikely to be the original Aurora CMGR service, and could be something else entirely claiming an effectively abandoned port.
The Honest Reality
Port 364 represents something genuine about Internet infrastructure: the registry is filled with ghosts. Services that seemed important enough to claim a well-known port number, that went through the IANA assignment process, that had contact persons and official documentation, and then disappeared.
The Internet is built on these layers of abandoned standards. Most ports carry living protocols—SSH on 22, HTTPS on 443, protocols that millions of people depend on every second. But scattered throughout the registry are services like Aurora CMGR, where the only evidence they existed is the port number they left behind.
Port 364 is a ghost. The registry dutifully lists its assignment. Security scanners note it has been associated with malware in the past (as almost any unused port eventually is).2 And somewhere, maybe, an old system still runs Aurora CMGR, connecting to something we've collectively forgotten.
But probably not.
Related Ports
Other ports in the nearby well-known range with actual documented services:
- Port 365 — unassigned
- Port 366 — ODMR (On-Demand Mail Relay)
- Port 367 — MortgageWare
- Port 363 — RSVP Tunnel
Frequently Asked Questions
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