Port 2839: NMSigPort — A Name with No Story

What Range This Port Belongs To

Port 2839 sits in the registered port range: 1024 through 49151. These ports are managed by the Internet Assigned Numbers Authority (IANA), which maintains a registry of service names and their assigned port numbers.¹

The registered range was designed for applications that need a predictable, consistent port number — things like database servers, game servers, and middleware. Unlike the well-known ports (0–1023), registered ports don't require elevated privileges to bind on most operating systems. Unlike the dynamic/ephemeral range (49152–65535), they're meant to be stable and identifiable.

The idea is that if your software needs a home on the network, you register a port so other software knows where to find you.

The IANA Registration

Port 2839 is listed in the IANA registry as NMSigPort — assigned to both TCP and UDP — registered by someone named Peter Egli.¹

That's where the story stops.

There is no RFC for NMSigPort. There is no public documentation. There is no software with a meaningful user base that identifies itself as using port 2839 for NMSigPort. The name suggests "Network Management Signaling Port," but that's interpretation, not documentation. The registration exists; the protocol, in any practical sense, does not.

This happens more often than you'd expect in the registered port range. Someone with a project or an idea submits a registration, IANA adds it to the list, and then the project never ships, or ships without ever meaningfully using the registered port, or disappears. The name tag stays in the registry indefinitely.

Security History

Some port databases flag port 2839 in amber or red, noting that malware has historically used this port for communications.² This is worth understanding clearly: malware will use any open port that isn't actively blocked or monitored. A port being exploited by malware in the past says nothing meaningful about the port itself — it says something about what attackers do when they need a channel that won't be immediately noticed.

An obscure registered port with no well-known service is actually attractive to malware for exactly that reason: it won't trigger obvious alarms, and defenders may assume something legitimate owns it.

How to Check What's Listening

If you see traffic on port 2839 and want to know what's using it:

On Linux/macOS:

# Show what process is listening on port 2839
ss -tlnp | grep 2839

# Or with lsof
lsof -i :2839

On Windows:

netstat -aon | findstr :2839

The process ID from those commands will let you look up the process name in your task manager or with ps.

If something is listening on port 2839 and you don't recognize what it is, that's worth investigating — not because NMSigPort is dangerous, but because any unexpected listener is worth understanding.

Why Empty Registrations Matter

Port 2839 illustrates a real tension in how the port registry works. IANA's registry is meant to bring order — a single source of truth for which port belongs to which service. But registrations are easy to claim and hard to revoke. The result is thousands of registered ports that are, in practice, unclaimed territory: officially spoken for, functionally abandoned.

This creates ambiguity. Software vendors, system administrators, and security tools can't always tell whether a port is legitimately in use by its registered service or whether it's been squatted by something else entirely.

The honest answer for port 2839: it has a name, it has a registration, and beyond that, it's an open question.