Port 2643: GTE-SAMP — A Registered Port Nobody Uses

What Port 2643 Is

Port 2643 sits in the registered port range (1024–49151). These ports are allocated by IANA to specific services and applications — not reserved like the well-known ports below 1024, but claimed.

Port 2643 is claimed. By GTE.

According to the IANA Service Name and Transport Protocol Port Number Registry, port 2643 is assigned to a service called GTE-SAMP, registered on both TCP and UDP by Asher Altman at GTE Government Systems Corporation (gsc.gte.com). ¹

That domain has been dead for over twenty years.

What GTE-SAMP Is (or Was)

GTE — General Telephone and Electronics — was one of the largest telecommunications companies in the United States. In 2000, GTE merged with Bell Atlantic to form Verizon. GTE Government Systems Corporation was its defense and government contracting arm.

SAMP almost certainly stood for some kind of network management or monitoring protocol used internally by GTE's government systems division. No public RFC was ever written for it. No public documentation survived. Whatever it did — monitoring telecom infrastructure, managing network elements, something else entirely — it was never deployed beyond GTE's own walls.

The registration is a timestamp: sometime in the 1990s, someone at GTE Government Systems thought this port number would matter, filed for it with IANA, and then either never shipped the software or shipped it in a context that disappeared when GTE did.

What Actually Uses Port 2643 Today

Nothing intentional.

If you see traffic on port 2643, the possibilities are:

• Nothing — it's closed and you're looking at a probe or scan
• Malware — attackers sometimes bind to obscure registered ports precisely because firewalls don't block them by default and no legitimate service holds the port
• Some application's dynamic choice — software occasionally lands on ports like this when grabbing an available socket
• A misconfigured or custom application — someone chose this port arbitrarily for an internal tool

There is no widespread legitimate software that uses 2643. If you find something listening here, investigate it.

How to Check What's Listening on This Port

On Linux or macOS:

# Show which process is listening on port 2643
sudo lsof -i :2643

# Or with ss (Linux)
sudo ss -tlnp | grep 2643

On Windows:

# Show listening ports with owning process IDs
netstat -ano | findstr :2643

# Match PID to process
tasklist | findstr <PID>

From the network:

# Check if port 2643 is open on a remote host
nmap -p 2643 <target>

Why Ports Like This Exist

The registered port range was designed to bring order to port assignment — a way for applications to stake out territory so two pieces of software don't accidentally collide on the same number. Thousands of ports were claimed in the 1990s and early 2000s by companies building products that were eventually abandoned, acquired, or simply never shipped.

Port 2643 is one of those. Officially owned, practically vacant — a quiet corner of the address space where a piece of 1990s telecom history registered its name and then faded out.

The IANA registry does not reclaim ports. Once assigned, they stay assigned, even when the companies behind them vanish. The registry is, in places, a fossil record of corporate ambition.