Port 1223 belongs to the registered ports range (1024-49151). These ports are assigned by IANA for specific services upon application by a requesting entity. Unlike well-known ports (0-1023), registered ports can be used by ordinary user processes without requiring elevated privileges.1
What runs on port 1223
Port 1223 is officially registered for TGP (TrulyGlobal Protocol), also known as "The Gur Protocol"—named after Gur Kimchi of TrulyGlobal.2 The protocol was designed for application sharing and collaboration, and there's evidence it was used with Microsoft NetMeeting for application sharing functionality.3
This is unusual. Most protocols have technical names. BGP. SMTP. DNS. But someone registered a protocol and named it after a person—a small act of personality in a world of RFC numbers and technical committees.
The person behind the protocol
Gur Kimchi is a technology leader who later became known for pioneering Amazon Prime Air's drone delivery program. Before Amazon, he held senior positions at Microsoft and has served on standards committees for FAA, NASA, IETF, ITU-T, and ICAO.4 The TrulyGlobal Protocol appears to be from an earlier chapter in his career, focused on collaboration and application sharing technology.
What happened to TGP
TrulyGlobal Protocol is rarely seen on modern networks. Microsoft NetMeeting—where TGP saw some use for application sharing—was discontinued in favor of newer collaboration tools. The protocol remains officially registered to port 1223, but it's effectively obsolete.
This is the reality of the registered ports range. Companies and developers register ports for services they believe will matter. Some become essential infrastructure. Others fade when the software that used them disappears.
Why registered ports matter
The registered ports range (1024-49151) serves as middle ground. It's not the critical infrastructure of well-known ports (0-1023), but it's also not the temporary chaos of dynamic ports (49152-65535). When a developer registers a port, they're saying: "This service will exist long enough that it needs a stable address."5
Some registered ports—like 3306 for MySQL or 5432 for PostgreSQL—become so widely used they're effectively well-known. Others, like port 1223, get registered with good intentions and then quietly fade away.
Checking what's listening on port 1223
On Linux or macOS:
On Windows:
If something is listening on port 1223 on your system, it's either legacy software that still uses TGP, or more likely, another application that chose to use this port because it's rarely claimed.
The human thread
Port 1223 carries something beyond its protocol specification. It carries ambition—the belief that a collaboration protocol would matter enough to deserve a permanent port number. It carries personality—the decision to name it after a person rather than an acronym. And it carries the honest reality that most things we build eventually fade, leaving behind only a number in a registry and a footnote in Internet history.
The Gur Protocol is mostly forgotten now. But port 1223 remains registered, a small monument to the work someone cared enough to name after themselves.
Frequently Asked Questions About Port 1223
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