Port 716: IRIS-BEEP — The Registry Query Port That Lived Two Lives

Port 716 was officially assigned to IRIS-BEEP (Internet Registry Information Service over BEEP), a protocol for querying domain and IP address registry information. But it also lived a second life as part of Mac OS X's RPC infrastructure for NetInfo, Apple's now-deprecated directory service.

Same port number. Different protocols. Different purposes. This is how the Internet actually works—official assignments coexist with unofficial uses, and somehow it all mostly works.

What Is IRIS-BEEP?

IRIS-BEEP is defined in RFC 3983¹, published in January 2005. It's a way to query Internet registries—the databases that track who owns which domain names and IP address blocks—using BEEP (Blocks Extensible Exchange Protocol) as the transport layer.

The idea: instead of fragmented, inconsistent registry lookup tools, create a standardized protocol for querying WHOIS-style information across different registries. IRIS would let you ask "who owns this domain?" or "what network does this IP belong to?" in a uniform way.

Port 716 was assigned for this purpose. TCP only, as specified in the RFC.

The Mac OS X Connection

Here's where it gets interesting: port 716 also appears in the range of ports (600-1023) used by Mac OS X RPC-based services², specifically for NetInfo.

NetInfo was Apple's hierarchical directory service used in NeXTSTEP, OpenStep, and Mac OS X Server. It stored administrative data—user accounts, printers, network services, filesystem mounts. The netinfod daemon used RPC (Remote Procedure Call) to communicate, and port 716 fell within the range of ports it could use.

This wasn't an official IANA assignment conflict—it was just how Mac OS X used ports in practice. NetInfo is long deprecated (replaced by Open Directory), but for years, port 716 served dual purposes: officially assigned to IRIS, practically used by Macs for directory services.

Why IRIS Never Took Off

Despite the RFC and the official port assignment, IRIS-BEEP never saw widespread adoption. Registry information queries remained fragmented across different WHOIS servers and web interfaces. The protocol was sound, but the ecosystem didn't converge around it.

So port 716's official assignment exists mostly as a historical footnote—a good idea that didn't gain traction.

What Well-Known Ports Mean

Port 716 falls in the well-known port range (0-1023), which is controlled by IANA³. These ports are supposed to be assigned to specific services by formal process. Applications and protocols in this range are expected to have stable, documented purposes.

But reality is messier. Well-known ports can be:

• Officially assigned but rarely used (like IRIS-BEEP)
• Officially assigned and also used unofficially for something else (like NetInfo's use of this port)
• Unassigned but widely used anyway

Port 716 is a case study in the gap between official assignments and actual network behavior.

Checking What's Using Port 716

To see if anything is listening on port 716 on your system:

Linux/Mac:

sudo lsof -i :716
sudo netstat -tulpn | grep :716

Windows:

netstat -ano | findstr :716

If you see something listening, it's probably not IRIS-BEEP (unless you're running a very niche registry service). It could be a legacy Mac OS X service, or something else entirely that decided this port number looked available.

Why Unassigned and Underused Ports Matter

The Internet has 65,535 ports per protocol (TCP/UDP). Only a fraction are actively used. But every assigned port—even the ones nobody uses—represents an intention, a moment when someone thought "we should standardize this."

Port 716 shows that port assignments are proposals, not laws. IANA can assign a port, but adoption is voluntary. And sometimes the same port serves different masters in different contexts.

This isn't a bug. It's how a decentralized system works. The assignments provide guidance. The network does what it needs to do.