Port 333 sits in the well-known port range (0-1023), officially assigned by IANA to something called "texar" — the Texar Security Port. Both TCP and UDP. Registered to Eugen Bacic.
If you've never heard of it, that's because the company behind it doesn't exist anymore.
What Texar Was
Texar was a Canadian startup founded in Ottawa around 1999. They built a product called SecureRealms — a Java-based policy management system for controlling access to files and data across enterprise networks.1 It was designed for the era when companies were figuring out how to secure information as it moved across the Web and peer-to-peer environments.
The company filed a patent for their computer security system in March 2000.2 They registered port 333 with IANA for their security service. And then, sometime in the years that followed, the company disappeared.
The patent was abandoned. The product is gone. But port 333 remains in the IANA registry, officially assigned to "texar" forever.
What This Port Does Now
Mostly nothing. Port 333 is not used by any widespread service today. You might occasionally see it flagged in security scans — some historical malware used port 333 for communication,3 likely because it was assigned but rarely monitored.
In theory, you could run something on port 333. Some network monitoring tools use it unofficially for collecting statistics or exchanging control messages. But there's no standard, no protocol, no living ecosystem around this port.
Why This Matters
Port 333 is a reminder that the Internet's infrastructure is built on human decisions that outlive the humans who made them. Texar reserved this port number for a security product that was supposed to protect enterprise data. The company failed. The product vanished. But the reservation remains in the official registry, a permanent marker of something that tried to exist.
The well-known port range (0-1023) is supposed to be for foundational Internet services — things like HTTP, SSH, DNS. Port 333 sits among them, assigned but dormant, a ghost in the machine.
The Well-Known Port Range
Ports 0-1023 are called "well-known ports" or "system ports." IANA assigns them to services that need to be globally recognizable. To bind to one of these ports, a program typically needs root or administrator privileges — it's a privileged operation because these ports are supposed to be trusted.
Port 333 has that designation. It's in the same category as SSH (22), SMTP (25), and HTTPS (443). But unlike those ports, which carry millions of connections every second, port 333 carries almost nothing.
Checking What's Listening
If you want to see if anything is using port 333 on your system:
On Linux or macOS:
On Windows:
You'll probably see nothing. And that's the truth of port 333 — it's assigned, it's official, but it's empty.
The Strange Beauty of Abandoned Ports
The Internet is full of these. Ports assigned to companies that died, protocols that never took off, services that seemed important in 1999 and disappeared by 2005. Port 333 is one of them.
Texar tried to build something meaningful — a way to secure data in the early days of distributed enterprise networks. They went through the process of registering with IANA. They got a port number. They built a product. And then the market moved on, the company closed, and all that's left is this: a number in a registry, a line in a database, a port that will be associated with "texar" forever even though Texar is gone.
It's honest in a way. The Internet remembers what we tried to build, even when we fail.
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