Port 441 sits in the well-known range (0-1023), reserved by IANA for services important enough to claim a permanent address. It was assigned to decvms-sysmgt—DEC VMS System Management—a protocol designed for managing Digital Equipment Corporation's OpenVMS systems.12
You probably don't see traffic on port 441 anymore. But it's still there, registered, waiting. A monument to a technology that mattered.
What It Was For
The decvms-sysmgt protocol allowed an Argus client (typically running on a PC) to communicate with an OpenVMS system for remote management—without requiring a login session.2 System administrators could monitor, configure, and maintain DEC machines over the network using this dedicated channel.
This was system management before web interfaces. Before SSH dashboards. Before cloud consoles. Port 441 was the door through which administrators reached into OpenVMS machines to keep them running.
The OpenVMS Era
OpenVMS first appeared in 1977 as VMS, developed by Digital Equipment Corporation.3 It ran on DEC's VAX minicomputers—machines that dominated universities, research labs, and corporate data centers throughout the 1980s and early 1990s.
OpenVMS was renowned for its clustering technology (invented by DEC engineers), which allowed multiple physical machines to act as a single system with extraordinary uptime.3 The operating system was designed to run continuously through hardware maintenance, software upgrades, and failures. It was the kind of reliability that earned religious devotion from its administrators.
Port 441 was part of that ecosystem—a small piece of infrastructure that helped keep those legendary uptimes running.
What Happened to DEC
Digital Equipment Corporation was once the second-largest computer company in the world. By the mid-1990s, the rise of personal computers and client-server architectures eroded DEC's minicomputer business. Compaq acquired DEC in 1998. Hewlett-Packard acquired Compaq in 2002. OpenVMS survived these transitions and still exists today, now maintained by VMS Software, Inc.4
But port 441—assigned in an era when DEC's influence was strong enough to claim well-known port numbers—sees almost no traffic now. The Argus clients are gone. The VAX machines are gone. The administrators who knew this protocol have mostly retired.
Why Unassigned Ports Matter
Port 441 isn't truly unassigned—it's assigned to a service that barely exists anymore. But it illustrates something important about the well-known port range: these numbers are permanent assignments. They don't expire when the company dies or the protocol fades into obscurity.
The well-known range (0-1023) is a historical record. Each number tells a story about what mattered enough, when IANA was handing out addresses, to deserve a permanent place in the Internet's namespace.
Port 441 says: Digital Equipment Corporation mattered. OpenVMS mattered. The engineers who built remote system management protocols mattered.
How to Check What's Using Port 441
On Linux or macOS:
On Windows:
You'll probably find nothing. Port 441 is quiet now.
Related Ports
- Port 442 — cvc-hostd, another obscure system management protocol
- Port 443 — HTTPS, the port that carries encrypted web traffic everywhere
- Port 22 — SSH, which replaced protocols like decvms-sysmgt for remote system management
The Honest Truth
Port 441 doesn't carry meaningful traffic anymore. The protocol it was designed for belongs to an era of computing that ended decades ago. But the port number remains registered, a small memorial in the IANA registry.
Every time you scan the well-known port range, you're reading archaeology. Port 441 is one of the fossils—a reminder that the Internet was built on layers of technologies that came before, each one essential in its moment, most of them forgotten now.
Digital's empire fell. OpenVMS survives in niches. Port 441 remains assigned, waiting for Argus clients that will never connect again.
Was this page helpful?