Port 722 lives in the well-known range (0-1023), reserved for system services assigned by IANA. It was designated for Mac OS X RPC-based services, primarily NetInfo—Apple's hierarchical distributed database for managing administrative data on Mac OS X Server systems.1
NetInfo is dead. Apple deprecated it years ago. But port 722 still appears in port scans, firewall configurations, and security documentation. The assignment is permanent.
What NetInfo Did
NetInfo stored the administrative backbone of Mac OS X Server: user accounts, group memberships, email configurations, printer settings, NFS mount points, and other network resources. It was hierarchical and distributed—servers could share administrative databases, and changes propagated through the NetInfo hierarchy.
For a time in the late 1990s and early 2000s, this was how you managed multiple Mac servers. Port 722 carried the RPC calls that made the distributed database work.
The RPC Service Range
Port 722 sits in a broader range (600-1023) that Apple used for various RPC-based services. RPC—Remote Procedure Call—is the mechanism that lets programs on different machines call functions as if they were local. NetInfo used this to query and update administrative data across networked systems.
The port carried TCP traffic for these RPC operations. When a Mac OS X Server needed to look up a user account or verify group membership, those queries often traveled through port 722.
Why It Still Appears
Even though NetInfo is gone, port 722 remains in the IANA registry and in countless security tools, network scanners, and firewall rule sets. Well-known port assignments don't expire. They're permanent archaeological layers.
Security scanners still check for open port 722. Firewall administrators still see it in default Apple port lists. Network monitoring tools still flag it as "Mac OS X RPC / NetInfo." The infrastructure remembers what the operating system has forgotten.
What Replaced It
Apple moved to Open Directory, which uses LDAP (port 389) and Kerberos (port 88) instead of NetInfo's proprietary RPC system. By Mac OS X 10.5 Leopard (2007), NetInfo was fully deprecated. Modern macOS systems don't use port 722 at all.
But the port assignment persists. It's a fossil record of how distributed systems worked before LDAP became the standard.
Checking Port 722
To see if anything is listening on port 722:
On macOS/Linux:
On Windows:
On modern systems, you'll find nothing. The port sits empty, waiting for a service that will never return.
Security Considerations
If you find port 722 open on a modern system, it's worth investigating. NetInfo hasn't been used in nearly two decades. An open port 722 might indicate:
- An extremely old Mac OS X Server installation (pre-2007)
- A misconfigured service binding to the wrong port
- Potentially suspicious activity mimicking old Apple services
Close it unless you're maintaining a museum of Mac OS X Server history.
Why Unassigned Ports Matter
Port 722 isn't technically unassigned—it was officially designated for Mac OS X RPC services. But it functions like an unassigned port on modern networks: reserved, documented, but unused.
This is common. The IANA registry contains hundreds of ports assigned to services that no longer exist, protocols that were never widely adopted, and companies that went out of business decades ago. The port numbers remain allocated, permanently removed from the pool of available addresses.
It's inefficient but necessary. Port assignments must be stable. You can't reassign port 722 to something else just because NetInfo died. Too many firewalls, too much documentation, too many security tools still reference it. The cost of changing it exceeds the value of reclaiming one port number.
So port 722 stays in the registry, a permanent marker of what Mac OS X Server used to be.
Related Ports
- Port 389 — LDAP, what replaced NetInfo for directory services
- Port 88 — Kerberos, the authentication system that supplanted NetInfo's user management
- Ports 600-1023 — The broader range Apple used for various RPC-based services
Frequently Asked Questions About Port 722
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