Port 780 is a well-known port officially assigned by IANA to "wpgs"—a service name that sounds cryptic because almost nobody uses it anymore. This port was designated for Mac OS X RPC-based services, particularly NetInfo, Apple's directory service system.1
The only problem: NetInfo has been dead since 2005.
What NetInfo Was
NetInfo was a hierarchical distributed database that Mac OS X used to track administrative data—user accounts, group permissions, email configurations, printers, network filesystems, and other system resources.2 It ran on RPC (Remote Procedure Call) services across the well-known port range 600-1023, with port 780 among those assigned for this purpose.3
In its time, NetInfo was essential to Mac OS X Server's infrastructure. Every permission, authentication, and resource lookup potentially touched this system.
Why It Disappeared
Mac OS X Tiger (10.4) was the last version to support NetInfo. When Leopard (10.5) shipped in 2007, Apple completely phased it out and replaced it with Open Directory—a standards-based LDAP directory service.4
Instead of NetInfo's proprietary database, Apple moved to flat property list files in /var/db/dslocal/ and embraced industry-standard protocols. The NetInfo Manager tool was replaced by Directory Utility. The RPC-based architecture gave way to LDAP.5
Port 780, assigned to a Mac OS X service, became assigned to nothing in practice.
The Well-Known Port Range
Port 780 sits in the well-known port range (0-1023), reserved for system services and assigned exclusively by IANA. These ports require root privileges to bind on Unix-like systems—a security measure to prevent ordinary users from impersonating critical services.
Being in this range means port 780 was considered important enough to warrant official assignment and protection. It also means the port can't be reassigned casually. IANA doesn't revoke well-known port assignments just because a service dies.
So port 780 remains officially assigned to wpgs, pointing to a service that vanished two decades ago.
What Uses Port 780 Now
In practice, very little. Some sources report that rpc.statd (the NFS status monitor daemon) has been observed using this port,6 but this appears to be incidental rather than standard. The rpc.statd daemon typically uses dynamic ports assigned by the RPC portmapper, not fixed well-known ports.
If you encounter traffic on port 780 today, it's either:
- Legacy systems still running ancient Mac OS X versions
- Software mistakenly or opportunistically using an "unoccupied" well-known port
- Malicious activity exploiting the fact that most people assume well-known ports are legitimate
Checking What's Listening
On Linux or macOS:
On Windows:
If something is listening on port 780 and it's not a Mac OS X Tiger system from 2005, you should investigate why.
Why Unassigned (and Dead) Ports Matter
The port system only works because assignments are stable and predictable. When you see traffic on port 443, you know it's HTTPS because that assignment is universal and enforced. When you see traffic on port 780, you should know it's... wpgs for NetInfo.
Except it's not. The service is gone. The assignment remains.
This creates a weird category: ports that are assigned but effectively unassigned. They're not available for reassignment (IANA doesn't revoke well-known port numbers lightly), but they're also not carrying their intended service anymore.
Port 780 is one of thousands of such ports—officially spoken for, practically empty. A reminder that the Internet's infrastructure accumulates history faster than it sheds it.
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