Port 262 occupies a strange space in the Internet's architecture. It has an official assignment. It's registered in IANA's ledger with a name: "arcisdms." It sits in the prestigious well-known ports range (0-1023), reserved for system services that passed IETF review or IESG approval. But ask what it actually does, and you'll find almost nothing.
What Is Arcisdms?
The honest answer: we don't really know.
Port 262 is assigned to both TCP and UDP for a service called "arcisdms."1 The name suggests "ARCIS Document Management System" or something similar, but no public documentation, RFC, or company website explains what this protocol does, who created it, or whether anyone still uses it.
It exists in port databases. Network scanners recognize it. But the protocol itself? Ghost.
The Well-Known Ports Range
Port 262 falls into the well-known ports range (0-1023), which makes its obscurity even stranger. These aren't casual assignments. Getting a system port requires going through IETF or IESG procedures—submitting documentation, demonstrating need, getting approval.2
Someone cared enough about arcisdms to request and receive a system port. Then the trail goes cold.
What We Know
From IANA's registry:3
- Service Name: arcisdms
- Port Number: 262
- Protocols: TCP and UDP
- Description: Arcisdms
That's it. No contact information. No RFC reference. No company name. Just a service name and a port number.
Security Note
Some security databases flag port 262 as having been used by malware in the past,4 though this doesn't mean the legitimate arcisdms service (whatever it is) has anything to do with that. Attackers use all sorts of ports, including obscure assigned ones that nobody's watching.
How to Check What's Listening
If you want to see if anything is using port 262 on your system:
On Linux/Mac:
On Windows:
If something is listening on port 262, you probably want to figure out what it is and whether you trust it.
Why This Matters
Port 262 represents something fascinating about Internet infrastructure: not everything gets documented. Not everything survives in public memory. Someone built something important enough to warrant a system port allocation. They got approval. They registered the name. And then... silence.
Maybe arcisdms is still running somewhere—on private networks, in legacy systems, in environments where documentation isn't public. Maybe it was discontinued decades ago and nobody bothered to return the port. Maybe it's actively used by a handful of organizations who don't advertise it.
The Internet is full of these ghosts. Protocols that mattered once. Services that someone needed. Standards that vanished.
Port 262 is proof that even in the official registry, mystery endures.
Related Ports
Other well-known ports in this range with clearer documentation:
- Port 161/162: SNMP (Simple Network Management Protocol)
- Port 389: LDAP (Lightweight Directory Access Protocol)
- Port 443: HTTPS (secure web traffic)
Frequently Asked Questions
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