Port 3474: TSP Automation — A Registered Ghost

What Port 3474 Is

Port 3474 sits in the registered port range (1024–49151) and carries an official IANA assignment: service name tsntspauto, described as "TSP Automation," registered circa 2004 on both TCP and UDP.¹

That registration is essentially all that exists. There is no public RFC, no surviving documentation, no known open-source implementation, and no observable deployments. Whatever TSP Automation was — a proprietary industrial control system, an internal enterprise tool, an abandoned startup project — it left no footprint.

What the Registered Range Means

Ports 1024–49151 are assigned by IANA on request. Unlike well-known ports (0–1023), which require IANA approval and are reserved for foundational protocols like HTTP, DNS, and SSH, registered ports are more loosely controlled. Any organization can request a reservation; IANA records it. Whether the software ever ships, scales, or survives is another matter entirely.

The registered range is littered with exactly this kind of entry: a name, a year, and silence.

Unofficial Uses

No commonly observed unofficial uses are documented for port 3474. Security researchers have not flagged it as a vector for known malware families. Firewall intelligence services show no notable traffic patterns associated with it.²

If you see port 3474 active on a machine, it is almost certainly an application that chose this port for internal reasons — not because of the IANA registration.

How to Check What's Using It

If port 3474 shows up in your network or on a host you manage, these commands will tell you what's listening:

Linux / macOS:

# Show what process is bound to port 3474
sudo ss -tlnp sport = :3474

# Or with lsof
sudo lsof -i :3474

Windows:

# Show listening processes with port 3474
netstat -ano | findstr :3474

# Then match the PID to a process name
tasklist | findstr <PID>

Network-wide (with nmap):

nmap -p 3474 <target-ip>

Why Ghost Registrations Matter

The IANA registry is permanent. Port 3474 will be "reserved for TSP Automation" indefinitely, even though TSP Automation appears to be gone. This matters for two reasons.

First, any application that wants to use port 3474 today has to decide whether to ignore the ghost registration or pick a different number. Most developers avoid registered ports regardless of whether anything is actually using them.

Second, ghost registrations quietly fragment the available port space. The registered range has 48,128 ports. Hundreds of them look exactly like 3474: assigned once, never deployed, never reclaimed. The ports don't expire.