Port 717 sits in the well-known port range (0-1023), officially assigned by IANA to Mac OS X RPC-based services, specifically NetInfo. But here's the thing: NetInfo has been dead for nearly two decades.
What NetInfo Was
NetInfo was Apple's directory service—the database that stored user accounts, system information, and network configuration on Mac OS X systems from version 10.0 through 10.4.1 It was inherited from NeXTStep and worked well enough for managing individual machines and small networks.
The problem: NetInfo was proprietary. It only worked on Apple systems. The rest of the world had moved to LDAP (Lightweight Directory Access Protocol), an open standard that could work across different operating systems.2
The End of NetInfo
In 2007, with the release of Mac OS X Leopard (10.5), Apple abandoned NetInfo entirely.3 They replaced it with Open Directory, which used LDAP and could interoperate with other systems. Apple didn't just deprecate NetInfo—they actively encouraged administrators to migrate away from it.
So port 717 became a ghost port. Still officially assigned, still sitting in the prestigious well-known range, but serving a protocol that no longer exists on any modern system.
What This Port Means Today
Port 717 is effectively unassigned in practice. You won't find NetInfo running on modern Macs. You won't find it running anywhere. The protocol is extinct.
But the port number remains in IANA's registry, a permanent record of a technology that didn't survive. This is what happens in the port system—assignments are rarely revoked. Once a port is assigned, it stays assigned, even after the service dies.
Why Ghost Ports Matter
Port 717 represents something important about how the Internet ages. We don't reclaim port numbers. We don't reassign them when services die. The well-known port range is full of these ghosts—protocols that were once important enough to deserve special numbers, but are now forgotten.
This is by design. Reassigning port numbers would be dangerous. Somewhere, someone might still be running that old service. Some legacy system in a basement might still depend on port 717. So we leave the number alone, marked as taken, even though nothing uses it anymore.
The port system accumulates history. Port 717 is a small piece of that history—a reminder that Apple once tried to go its own way with directory services, and then realized the rest of the world had a better answer.
Checking What's Listening
If you want to see what's actually listening on port 717 on your system (likely nothing):
On Linux or macOS:
On Windows:
If you see something listening on port 717, it's not NetInfo—that's impossible on any modern system. It's either a misconfigured service that grabbed the port by accident, or something deliberately using an abandoned port number because it knows no one else will claim it.
The Well-Known Range
Port 717 belongs to the well-known port range (0-1023), also called system ports. These ports are assigned by IANA through a formal process that requires IETF review or IESG approval.4 They're reserved for services considered important enough to deserve a permanent, low-numbered port.
Being in this range means port 717 was once significant. NetInfo mattered enough to Apple—and Apple mattered enough to the Internet—that this port was officially reserved. The fact that the service died doesn't diminish that historical importance.
Security Considerations
Port 717 shouldn't be open on any modern system. If you see it open during a security scan, investigate immediately. It's either:
- A misconfigured service using the wrong port
- Malware deliberately using an abandoned port to avoid detection
- An extremely old Mac OS X system (10.4 or earlier) that should have been retired years ago
Modern network security scanners still check port 717 because it's in the well-known range and should be closed.5 An open port 717 is a red flag.
Related Ports
- Port 1033 - Another NetInfo-related port used for dynamic binding
- Port 389 - LDAP, the protocol that replaced NetInfo
- Port 636 - LDAPS (LDAP over TLS), the secure version
Frequently Asked Questions About Port 717
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