What This Port Is
Port 1015 is officially assigned to ipcserver, a component of Apple's NetInfo RPC (Remote Procedure Call) infrastructure. 1 It occupies space in the well-known ports range (0-1023), which means IANA, the Internet Assigned Numbers Authority, explicitly allocated it—not just registered it, but reserved it. That carries weight.
The Range: Well-Known Ports (0-1023)
Ports 0 through 1023 are controlled by IANA. Unlike the registered port range (1024-49151) where anyone can request an assignment, well-known ports are scarce. There are only 1,024 of them. IANA allocates them deliberately, usually only to fundamental Internet services: DNS on 53, HTTP on 80, SMTP on 25. Getting a well-known port assignment used to mean something.
Port 1015 got one. Then the protocol it served became irrelevant.
The Protocol: NetInfo and RPC
NetInfo was Apple's distributed network information system for managing user directories and system configuration across networked Macs. Before centralized directory services like LDAP and Active Directory became standard, NetInfo provided similar functionality—but it never left the Apple ecosystem.
Port 1015 carried RPC calls between Mac OS X systems. If you had a network of Macintoshes, NetInfo could tell them: "Where do I find this user? What's the group membership? Where's the print server?" It worked. It solved a real problem in the 1990s.
Apple deprecated NetInfo in OS X 10.5 (Leopard, 2007). They moved to directory services standards like LDAP and Open Directory. By 2010, NetInfo was completely gone. Port 1015 stayed in the registry.
What Listens on Port 1015 Today
Almost nothing. If you scan port 1015 on a modern Mac, it won't be open. If you run a network scan across your office, you won't find it. The assignment persists because IANA doesn't unassign ports—once allocated, they're allocated forever. Backward compatibility, historical records, the theory that someone might need it again.
How to Check
To see if anything is actually listening on port 1015 on your system:
On macOS or Linux:
On Linux (newer):
On Windows:
If nothing appears, you've just confirmed what's true for virtually everyone: port 1015 is empty.
Why Unassigned (and Abandoned) Ports Matter
Port 1015 teaches something important about how the Internet works: it's not designed for perfection, it's designed for persistence. You can't delete ports without breaking documentation, breaking RFCs, breaking historical research. NetInfo is dead, but its port number lives on, a small memorial in the registry.
This matters because it shows that the port numbering system prioritizes stability over efficiency. There are only 65,536 ports total (TCP and UDP combined, across all numbers 0-65535). Port 1015 is essentially reserved real estate for a service nobody uses. Yet no one argues it should be reassigned, because the cost of reassigning it (breaking any documentation, any old scripts, any reference) outweighs the benefit of having one more empty port.
It's a beautiful example of how Internet infrastructure decisions made decades ago still constrain what's possible today.
Related Ports
- Port 111 (portmapper) — The RPC service discovery port that NetInfo's RPC calls would have queried
- Port 389 (LDAP) — The modern replacement for NetInfo's directory services
- Port 3659 (Apple sasl) — Other macOS system services in the well-known range
Frequently Asked Questions
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