Official assignment: VEMMI (VErsatile MultiMedia Interface)
Defined by: RFC 21221
Status: Assigned but obsolete
What VEMMI Was
VEMMI stands for "Enhanced Man-Machine Interface for Videotex and Multimedia/Hypermedia Information Retrieval Services"—a name that tells you everything about when it was designed.2
It was an attempt to save videotex. In the late 1970s and early 1980s, telecommunications companies and media organizations invested heavily in videotex—systems that delivered text and simple graphics to TVs through telephone lines.3 France had Minitel. The UK had Prestel. The US had various failed attempts.
By the early 1990s, videotex was dying. VEMMI was the response: an international standard that would make videotex multimedia, object-oriented, event-driven, and platform-independent.4 Everything the web was becoming, but standardized through ITU-T (International Telecommunication Union) and ETSI (European Telecommunications Standards Institute).
Port 575 was assigned by IANA as VEMMI's official well-known port.5
How It Worked
VEMMI operated as a client-server protocol over a single continuous TCP session. The client software—running on a PC or Mac—connected to a VEMMI multimedia server and received an interactive multimedia interface.6
URLs looked like this:
If you omitted the port, it defaulted to 575.1
The protocol supported multimedia content delivery, user interaction events, and worked across different network types: Internet, ISDN, or legacy videotex networks.6 It was designed to be the universal interface for online multimedia services.
The Timing Problem
VEMMI became an ITU-T International Standard (T.107) and a European Standard (ETS 300 709).2 That kind of international coordination takes years of committee work, technical refinement, and political negotiation.
RFC 2122 was published in March 1997.1
Netscape Navigator had been released in 1994. By 1997, the web had won. Nobody needed a standardized videotex protocol when HTTP and HTML already worked, were simpler, and had millions of pages already published.
What Happened to Port 575
VEMMI never saw widespread deployment. The port remains officially assigned to the protocol, but you won't find VEMMI servers in 2026.
There have been reports of malware occasionally using port 575 opportunistically—a common pattern for assigned-but-unused ports.78 If something is listening on port 575 on your network, it's almost certainly not VEMMI.
Why This Port Matters
Port 575 is a reminder that standardization has a cost: time. VEMMI was thoughtfully designed, internationally coordinated, and formally blessed by the organizations that manage global telecommunications standards. And none of that mattered because the web moved faster.
The Internet doesn't wait for committees. By the time VEMMI was ready, the problem it solved had already been solved differently—by a physicist at CERN who just wanted to share documents.9
Checking Port 575
To see if anything is listening on port 575:
On Linux/Mac:
On Windows:
If you find something listening on this port, it's worth investigating—it's almost certainly not VEMMI.
Related Ports
- Port 79 — Finger protocol, another pre-web information service
- Port 70 — Gopher, which also lost to HTTP
- Port 80 — HTTP, the protocol that won
Frequently Asked Questions About Port 575
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