Port 2117: Mentaclient — A Registered Port with a Forgotten Purpose

Port 2117 sits in the registered port range (1024–49151). These are ports that aren't reserved for core Internet infrastructure like the well-known ports below 1024, but they aren't random either. An organization or developer applied to IANA, made a case for needing a dedicated port number, and received one. Port 2117 went through that process.

Its registered name: mentaclient.

Its sibling on port 2118: mentaserver.

Beyond the names, the trail goes cold. No surviving documentation, no traceable company, no source code, no RFC. Whatever Menta was — a client-server application, a proprietary protocol, an internal enterprise tool that briefly sought a public registration — it is gone.¹

What the Registered Range Means

The registered port range exists because application developers needed stable, predictable port numbers that wouldn't collide with each other. Before IANA formalized the registration process, software would pick ports arbitrarily, and two unrelated applications would end up fighting over the same number.

Registration doesn't mean a port is important or widely used. It means someone, at some point, asked for it. IANA records the assignment and moves on. Whether the software succeeded, shipped, or survived is not IANA's concern.

Port 2117 is a reminder that the registry is a ledger, not a museum. It records what was claimed, not what persists.

Is This Port Dangerous?

An unassigned or lightly-documented port isn't inherently dangerous. What matters is whether something is actually listening on it on your system. If port 2117 shows up in your network scan and you didn't put anything there, investigate. The port name means nothing — what matters is the process behind it.

How to Check What's Using This Port

On Linux or macOS:

# Show what process is listening on port 2117
sudo ss -tlnp | grep 2117

# Or with lsof
sudo lsof -i :2117

On Windows:

netstat -ano | findstr :2117

The output will show the process ID (PID). Cross-reference that with Task Manager or ps aux to identify the application.

With nmap (scanning a remote host):

nmap -p 2117 -sV target-host

The -sV flag attempts to identify the service — though for an undocumented port, nmap may just report the connection state.

Why Forgotten Ports Matter

Every port in the registered range that belongs to dead software is a port that can't be cleanly reassigned. IANA doesn't revoke registrations — once assigned, a port number carries its name indefinitely, even if the software vanished decades ago. This is part of why the registered range fills up slowly with ghost entries: ports that are technically claimed but practically ownerless.

It also means that if modern software happens to use port 2117 — whether a game server, a development tool, or a monitoring agent — it's operating outside any official registration. The port works fine. But if there's ever a conflict, there's no authority to appeal to.

Related Ports

• 2118 — mentaserver, the registered server-side companion to port 2117's client role²
• 1024 — the boundary between well-known ports (0–1023) and the registered range
• 49151 — the upper boundary of the registered range; above this are ephemeral/dynamic ports