Range: Well-known ports (0-1023)
Status: Historically associated with Apple NetInfo; largely obsolete
Protocol: TCP/UDP
What Port 818 Was
Port 818 sits in the well-known port range—the first 1,024 ports reserved by IANA for fundamental Internet services. Most ports in this range carry protocols that define how the Internet works. Port 818 is different. It was part of Apple's walled garden.
In older versions of Mac OS X (before 10.5 Leopard in 2007), port 818 was used by NetInfo—a hierarchical distributed database that stored administrative information. User accounts. Group memberships. Email configurations. Network file system mounts. Printers. Everything a Mac needed to know about its network environment.
NetInfo came from NeXTSTEP, the operating system Steve Jobs built after leaving Apple. When Apple bought NeXT and built Mac OS X on top of NeXTSTEP's foundation, NetInfo came along for the ride.1
How NetInfo Worked
NetInfo was a directory service—a way for computers on a network to share administrative data. Instead of each Mac maintaining its own isolated list of users, NetInfo let them query a central database. This made it possible to have network-wide user accounts, where you could log into any Mac on the network with the same credentials.
The service used RPC (Remote Procedure Call) to communicate between Macs. Port 818, along with other ports in the 600-1023 range, carried these RPC-based services.2
What Happened to It
Apple killed NetInfo completely in Mac OS X 10.5 (Leopard), released in October 2007. Its functionality was replaced by Open Directory, which had been part of Mac OS X Server since version 10.1 or 10.2. Open Directory used standard protocols like LDAP instead of Apple's proprietary RPC system.
This means port 818 stopped being relevant almost two decades ago. Modern Macs don't use it. The service that gave this port purpose no longer exists.
Current Status
Port 818 exists in a strange limbo:
- Technically well-known — It's in the 0-1023 range that IANA reserves for fundamental services
- Practically obsolete — The only service commonly associated with it has been dead since 2007
- Likely unassigned — While historical sources reference NetInfo's use of this port range, official IANA documentation doesn't clearly assign port 818 to any current service
Most well-known ports are either famous (like 80 for HTTP or 443 for HTTPS) or actively dangerous (like 23 for Telnet's plaintext passwords). Port 818 is neither. It's just abandoned.
Checking What's Listening
If you want to see if anything is actually using port 818 on your system:
On Linux/Mac:
On Windows:
Odds are, nothing is listening. And if something is, it's worth investigating—because legitimate software has no reason to be using this port anymore.
Why Unassigned Ports Matter
The well-known port range (0-1023) is supposed to be the stable foundation of the Internet. These ports need root privileges to bind to, which is a security feature—it prevents random applications from impersonating critical services.
But not every port in this range is actually assigned. Some were reserved for services that never took off. Some were used by proprietary systems (like NetInfo) that died. Some remain genuinely unassigned, waiting for a protocol important enough to claim them.
Port 818 is a reminder that the Internet's foundation isn't just technical—it's historical. The port numbers we use today carry the fossils of dead protocols, abandoned projects, and systems that once seemed permanent but weren't.
Frequently Asked Questions
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