Port 602 is officially assigned by IANA for XML-RPC over BEEP (Blocks Extensible Exchange Protocol). It's a protocol that combines XML-based remote procedure calling with BEEP's structured message exchange framework.1
What runs on this port
XML-RPC over BEEP is defined in RFC 3529.2 It takes the XML-RPC format—which normally runs over HTTP—and layers it on top of BEEP instead. BEEP provides features that HTTP doesn't: channel multiplexing, formal message sequencing, and more sophisticated error handling.
The protocol works on both TCP and UDP, though TCP is the primary transport. When a BEEP session starts on port 602, the XML-RPC profile is identified as http://iana.org/beep/transient/xmlrpc during channel creation.3
Why this protocol exists
In the early 2000s, XML-RPC was popular for remote procedure calls between systems. But running it over plain HTTP had limitations—no built-in session management, limited error handling, and no way to multiplex multiple operations over a single connection.
BEEP was designed to solve these problems. It's an application protocol framework that provides structure, reliability, and features that HTTP didn't have. Port 602 exists because someone believed XML-RPC would work better on BEEP than on HTTP.
They were probably right, technically. But HTTP won anyway. Sometimes "good enough" beats "better."
The BEEP framework
BEEP (Blocks Extensible Exchange Protocol) was specified in RFC 3080 as a framework for building application protocols. Instead of each protocol reinventing connection management, BEEP provided:
- Channel multiplexing — Multiple logical channels over one TCP connection
- Message sequencing — Guaranteed ordering and acknowledgment
- Profile negotiation — Formal handshaking for protocol capabilities
- Error handling — Structured error messages instead of HTTP status codes
XML-RPC over BEEP was one of several protocols built on this framework. Others included SOAP over BEEP and various proprietary enterprise protocols.
What happened to BEEP
BEEP represented a philosophy: that the Internet needed more structured, formal protocols than the chaos of HTTP. It was designed for enterprise systems that needed reliability, proper error handling, and session management.
But HTTP evolved. Keep-alive connections, HTTP/2 multiplexing, and modern frameworks solved many of the problems BEEP was designed for—just in a messier, more pragmatic way.
Port 602 still exists in the IANA registry. The protocol still works. But if you're building RPC systems today, you're probably using gRPC, or REST over HTTP/2, or GraphQL. Not BEEP.
Other uses
Some older documentation mentions port 602 being used for "Repscmd" (Remote Execution Protocol for System Command) in IBM's Tivoli Storage Manager, and for certain Mac OS X RPC-based services like NetInfo.4 These appear to be historical uses or documentation errors—the official IANA assignment is for XML-RPC over BEEP.
Security considerations
If port 602 is open on your system and you're not running XML-RPC over BEEP (and you probably aren't), something unexpected is listening. BEEP itself has no built-in encryption—it relied on TLS wrapping, defined in RFC 3081.
The protocol never achieved widespread adoption, which means there's little modern security auditing and fewer maintained implementations. If you encounter port 602 in the wild, verify what's actually running before assuming it's legitimate.
How to check what's listening
On Linux or macOS:
On Windows:
If something is listening and you don't recognize it, investigate. Port 602 is obscure enough that unexpected usage is suspicious.
Why unassigned ports matter
Port 602 isn't unassigned—it has a formal IANA registration. But it represents something important: the gap between assignment and actual use. IANA registers thousands of ports for protocols that never gain traction. The registry is full of optimistic protocols that solved real problems but lost to simpler, scrappier alternatives.
Port 602 is a monument to the belief that the Internet could be more structured, more reliable, more engineered. That belief was correct. But messy pragmatism won anyway.
The lock icon in your browser uses port 443, not port 602. That tells you everything about how the Internet actually evolved.
آیا دا پاڼه ګټوره وه؟