Port 582: SCC Security — The officially assigned ghost

Port 582 sits in the well-known port range (0-1023), officially assigned by IANA¹ to a service called "SCC Security." Both TCP and UDP variants exist. And that's about all anyone knows.

What the Port Range Means

Ports 0-1023 are the well-known or system ports—reserved for fundamental Internet services and protocols.² Getting a well-known port assignment requires IETF Review or IESG Approval, the most stringent requirements in the port assignment process.³ These ports are privileged on most systems, requiring root or administrator access to bind to them.

Port 582 earned one of these coveted assignments. And then... nothing.

The Mystery of SCC Security

"SCC Security" appears in the IANA registry.⁴ It's registered for both TCP and UDP on port 582. But beyond the name, documentation is essentially nonexistent. No RFC defines it. No major software uses it. No network monitoring tools flag it as significant traffic.

The protocol exists in that peculiar state of being officially assigned but practically unknown—a ghost in the port registry.

Why This Matters

Unassigned and obscure ports like 582 serve an important purpose in the port ecosystem:

They remind us the Internet has history. Someone, somewhere, at some point thought SCC Security needed a well-known port. The protocol may have been important in a context we've forgotten, or it may have been abandoned before it ever shipped. The port number preserves that moment.

They create opportunities. If you're building something new and need a port, you can request reassignment of an unused well-known port, or register in the user port range (1024-49151). The IANA registry is not set in stone—it evolves as the Internet does.

They're useful for testing and private applications. Because port 582 sees essentially no legitimate traffic, network administrators sometimes repurpose it for internal monitoring tools or custom applications, knowing there's minimal risk of conflict.

How to Check What's Listening

On Linux or macOS:

# See what's listening on port 582
sudo lsof -i :582

# Or with netstat
sudo netstat -tulpn | grep :582

On Windows:

# Show processes using port 582
netstat -ano | findstr :582

If you see something listening on port 582, it's almost certainly not the original SCC Security service—it's either a custom application or something worth investigating.

The Takeaway

Port 582 is assigned. It's official. It's in the registry. And it's essentially unused.

That's not a failure. It's an artifact. The Internet is built on layers of history—protocols that mattered once, assignments that made sense in another era, decisions that seemed important at the time. Port 582 is one of those decisions, preserved in the registry, waiting quietly in case anyone ever needs it again.

Most ports tell stories about what the Internet is. Port 582 tells a story about what the Internet was—or what someone thought it might become.