Port 824: Unassigned — An empty room in the well-known range

Port 824 has no official service assignment. It's an empty room in a crowded building.

What Range Does This Port Belong To?

Port 824 sits in the well-known port range (0-1023). These are the system ports—the ones assigned by IANA to fundamental Internet services. Port 80 for HTTP. Port 443 for HTTPS. Port 22 for SSH. This is the range where every number carries weight.

But port 824? Unassigned.

According to IANA's registry, ports 811-827 (both TCP and UDP) have no official service assignments.¹ In a range where most ports were claimed decades ago, this cluster remains open.

Why Does This Matter?

The well-known port range is finite. Only 1,024 port numbers exist in this space, and they're the only ports that system processes can bind to by default on Unix-like systems (without elevated privileges). Having unassigned ports here is like having empty lots in downtown Manhattan—valuable, rare, and unlikely to stay empty forever.

When a new protocol needs official recognition, it can request assignment in this range. But IANA is conservative. The protocol needs to prove it's fundamental enough to deserve a well-known port. Most new services get assigned ports in the registered range (1024-49151) instead.

Known Unofficial Uses

There are no widely documented unofficial uses of port 824. It doesn't appear in malware databases or common service lists. It's genuinely unused—at least in any organized way.

This doesn't mean nothing can use port 824. Any application can bind to it. But without an official assignment or common convention, you're unlikely to find anything listening here on a typical system.

How to Check What's Listening on Port 824

On Linux or macOS:

# Check what's listening on port 824
sudo lsof -i :824

# Or using netstat
sudo netstat -tuln | grep :824

# Or using ss (modern alternative)
sudo ss -tuln | grep :824

On Windows:

# Check listening ports
netstat -ano | findstr :824

If nothing returns, nothing is bound to port 824—which is the expected result on most systems.

What Happens to Unassigned Ports?

Unassigned ports in the well-known range serve as a reserve. When new fundamental protocols emerge, IANA can assign them official port numbers. The bar is high—the protocol needs to be widely deployed or expected to become a core Internet service.

For now, port 824 waits. A door with no service behind it. An address with no occupant. Part of the Internet's infrastructure that remains, for now, unused.

Related Ports

Port 824 sits in a cluster of unassigned ports:

• Ports 811-827: Unassigned by IANA (both TCP and UDP)
• Port 810: FCP Datagram (one of the assigned ports just before this cluster)
• Port 828: itm-mcell-s (one of the assigned ports just after this cluster)