Port 950: Unassigned — A Ghost in the Well-Known Range

Port 950 sits in the well-known range (0-1023) but has no official service assigned by IANA. It's part of a block of ports (600-1023) that Apple historically reserved for RPC-based services on Mac OS X systems.¹

What Range This Port Belongs To

The well-known ports (0-1023) are assigned by IANA and require administrative privileges to bind to on Unix-like systems. This range contains most of the Internet's fundamental services—HTTP on 80, HTTPS on 443, SSH on 22.

Port 950 is in this range but unassigned. It's reserved space with no tenant.

Historical Use: Mac OS X RPC Services

On early Mac OS X systems, ports 600-1023 were used for RPC-based services like NetInfo—Apple's legacy directory service inherited from NeXT.²³

NetInfo stored local user accounts, group information, and system configuration. It was the database that told your Mac who you were and what you could do. Before Open Directory. Before LDAP became standard.

Port 950 falls within this RPC service range. While the available documentation doesn't specify exactly what ran on 950, it was part of the infrastructure for these services.

NetInfo was completely replaced by Open Directory in Mac OS X 10.5 Leopard (2007).² The ports remain, but the services they served are gone.

Current Status

Port 950 is mostly unused today. You might encounter it:

• On very old Mac OS X systems (pre-10.5) still running NetInfo
• In legacy network configurations that never got updated
• As a listening port for custom applications that picked an unused number

Checking What's Listening

To see if anything is using port 950 on your system:

On Linux/macOS:

sudo lsof -i :950

On Windows:

netstat -ano | findstr :950

If nothing returns, the port is unused. If something does, you've found either a legacy service or a custom application.

Why Unassigned Ports Matter

The well-known range (0-1023) is finite—only 1,024 ports. Some are essential (22, 80, 443). Some are historical artifacts (port 950). Some are assigned to protocols nobody uses anymore.

Unassigned ports in this range represent:

• Historical reservations that never got formally documented
• Space held for future use that never arrived
• Legacy services that died but left their ports behind
• Mistakes in documentation where assignments were never completed

Port 950 is a ghost. Part of a range that served Apple's directory services in the NeXT era, now mostly silent. The infrastructure moved on, but the port number remains—reserved in documentation, unused in practice.