Port 10200 — The Unassigned Middle Ground

What This Port Is

Port 10200 lives in the registered port range (1024-49151). This means someone, somewhere, asked IANA for permission to use it—but IANA hasn't actually assigned it an official service. The distinction matters: the port exists in the system's official records, but it's still a free-for-all.

What Actually Uses It

Nothing official. But in practice:

• IBM WebSphere Application Server ¹ runs its administrative console HTTP interface on port 10200
• FRISK Software's antivirus daemons (fpscand, f-protd) ² use this port on Unix systems for scanning requests

These are conventions, not assignments. The port isn't reserved for these services—they just showed up and started using it.

The Registered Port Limbo

Here's what makes this interesting: there are roughly 48,000 registered ports (1024-49151). The vast majority have no assigned service. IANA's registry is more museum than mandate—it documents what was requested, not what's actually in use.

Port 10200 could be running anything on your machine. WebSphere, an antivirus daemon, a custom game server, a development tool, or nothing at all.

How to Check What's Listening

macOS/Linux:

# See what's listening on port 10200
sudo lsof -i :10200

# Or check with netstat
sudo netstat -tulpn | grep 10200

Windows (PowerShell):

# Find what's using port 10200
netstat -ano | findstr :10200

# Get process name from PID
Get-Process -Id [PID from above]

Cross-platform (with nc/netcat):

# Test if port is open
nc -zv localhost 10200

Why This Matters

Port 10200 is honest about what it is: a number in a ledger with a few unofficial tenants. Most port numbers look like this—sitting between the famous ports (80, 443, 22) and the ephemeral chaos (49152+), doing real work without being officially acknowledged.

The port system evolved to handle this. IANA can't possibly assign every port to every service that needs one. So the middle 48,000 ports became a commons: officially recognized but freely available, with conventions rather than rules.

If you see port 10200 open on a system, check the process. It's probably WebSphere or antivirus software. But officially? It could be anything.