Port 2305: Unassigned — A Registered Port with No Known Owner

What Range This Port Belongs To

Port 2305 is a registered port, in the range 1024–49151. This range sits between the well-known ports (0–1023, reserved for foundational protocols like HTTP, DNS, and SSH) and the ephemeral ports (49152–65535, used temporarily by operating systems for outgoing connections).

Registered ports exist so that software vendors and service operators can stake a claim: "this is where my application lives." Anyone can apply to IANA for a registered port assignment, and the registry is meant to prevent two different services from stepping on each other.¹

The idea works better in theory than in practice. Thousands of registered port entries are outdated, abandoned, or impossible to research. Port 2305 is one of them.

The Ghost in the Registry

Some port databases list port 2305 as belonging to a service called MT ScaleServer (service name: mt-scaleserver). This entry appears to have propagated from an early IANA registration into secondary databases, which then copied each other.

The problem: there is no surviving documentation of what MT ScaleServer was, who made it, or what it did. No RFC. No product page. No company. The name suggests something industrial — perhaps software for managing weighing scales or scaled deployments — but this is speculation. Whatever MT ScaleServer was, it is gone, and it left almost no trace.

IANA's current records treat port 2305 as unassigned.² For practical purposes, this port belongs to nobody.

What Might Actually Be Running on Port 2305

If you see port 2305 open on a machine you're responsible for, the likely explanations are:

• Custom or in-house software that picked this port arbitrarily
• Legacy enterprise software from a vendor that quietly used this range
• Malware or unauthorized services that chose an obscure registered port to avoid detection

An open port 2305 isn't inherently alarming — but it warrants investigation, because there's no well-known legitimate service that should be listening there.

How to Check What's Listening

On Linux/macOS:

# Show which process owns port 2305
sudo ss -tlnp sport = :2305

# Or with lsof
sudo lsof -i :2305

On Windows:

# Show listening ports with process IDs
netstat -ano | findstr :2305

# Look up the process ID
tasklist /fi "pid eq <PID>"

These commands will tell you exactly which process has claimed the port. From there, check whether that process belongs to software you recognize and intended to install.

Why Unassigned Ports Matter

The port registry is a coordination mechanism, not an enforcement mechanism. Nothing prevents software from opening any port it wants — the registry just records intentions. When those intentions go undocumented, or when the software that filed the registration disappears, you're left with entries like port 2305: a name with no face, a claim with no claimant.

This is why security professionals treat unexpected open ports as signals worth investigating, regardless of what the registry says. The registry tells you what was planned. ss and lsof tell you what's actually happening.