Port 2937: pnaconsult-lm — A Registered Port with Nowhere to Go

What Port 2937 Is

Port 2937 is assigned by IANA to pnaconsult-lm — a license management service registered by a contact at nijssen.nl, a Dutch domain.¹ It operates on both TCP and UDP.

Beyond the registration, there is almost nothing to find. No widely used software runs on this port. No major service depends on it. It does not appear in firewall documentation, security advisories, or network configuration guides. It exists in the registry and essentially nowhere else.

The Registered Port Range

Port 2937 sits in the registered port range: 1024 through 49151.²

Here is how the three ranges work:

• Well-known ports (0–1023) — Assigned to foundational services. HTTP, HTTPS, SSH, DNS, SMTP. These are tightly controlled.
• Registered ports (1024–49151) — Assigned by IANA on request, for specific applications and services. Any organization can register a port here by submitting a request. Thousands have.
• Dynamic/ephemeral ports (49152–65535) — Not assigned to anyone. Used temporarily by operating systems for outbound connections.

The registered range is enormous — over 48,000 ports — and IANA has assigned a significant fraction of them. Many of those assignments belong to software that is obscure, discontinued, or never widely deployed. Port 2937 is one of these.

Why Unassigned-in-Practice Ports Matter

"Registered" does not mean "in use." When you see an unfamiliar port open on a system — especially one in the registered range — the IANA assignment tells you very little. The port might be running the registered service, a completely different application, or something you should be concerned about.

The practical implication: don't assume a port is safe because it has a name in a registry. Verify what is actually listening.

How to Check What Is Using Port 2937

On Linux or macOS:

# Show what process is listening on port 2937
sudo lsof -i :2937

# Or with ss (modern Linux)
sudo ss -tlnp sport = :2937

On Windows:

netstat -aon | findstr :2937

The output will include the process ID (PID). Cross-reference with Task Manager or tasklist to identify the application.

If you find something listening on port 2937 and you did not install pnaconsult-lm (you almost certainly did not), it is worth investigating what that process actually is.