Port 846 is officially unassigned by IANA, sitting in the well-known port range (0-1023) without a current service. But it wasn't always empty.
What Range This Port Belongs To
Port 846 falls in the well-known port range (0-1023), also called system ports. This range is controlled by IANA and reserved for services that need consistent, universally recognized port assignments. When a port in this range is unassigned, it means IANA hasn't designated an official service for it—at least not anymore.1
Well-known ports require administrative privileges to bind to on most systems. Even though port 846 is unassigned, you can't just grab it without root access.
The NetInfo Era
Port 846 has a history. It was used by NetInfo, an RPC-based directory service that ran on Mac OS X.2 NetInfo managed administrative data—user accounts, group configurations, email settings, NFS mounts, printer definitions, and other network resources. It was Apple's way of organizing system information hierarchically across networked Macs.
NetInfo operated across a range of ports (600-1023), with port 846 being one of them. If you ran a Mac network in the early 2000s, NetInfo was part of the infrastructure you dealt with.
Then Apple killed it. Mac OS X 10.5 (Leopard), released in 2007, removed NetInfo entirely.3 Apple replaced it with Open Directory, which used different protocols and different ports. NetInfo disappeared, but port 846 remained in the registry—officially unassigned, but carrying the ghost of what used to be there.
What This Means Today
If you scan port 846 on a modern network, you'll almost certainly find nothing. The protocol is gone. The service is dead. The port sits empty.
But "unassigned" doesn't mean "unused forever." Technically, any service could bind to port 846 locally. You could run your own application on it. But without an official IANA assignment, there's no guarantee that someone else's software won't also try to use it. Unassigned ports exist in a kind of limbo—available but not claimed.
How to Check What's Listening on Port 846
On Linux or macOS:
On Windows:
If nothing returns, the port is closed. If something does return, you've found either a legacy NetInfo installation (unlikely unless you're running a very old Mac) or something else that decided to use this port.
You can also use nmap to scan it remotely:
Why Unassigned Ports Matter
Most ports are unassigned. Out of 65,535 possible port numbers, only a fraction have official designations. The well-known range (0-1023) is more densely assigned than the others, but even here, gaps exist.
Unassigned ports represent possibility. They're the spaces between services—available for future protocols, experimental projects, or private applications. They also represent history. Some ports, like 846, were once assigned (informally or in practice) and then abandoned when the world moved on.
Port 846 is a reminder that the Internet's infrastructure isn't static. Protocols are born, thrive, and die. Services come and go. The port numbers remain, waiting for the next thing—or for nothing at all.
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