Port 3190: ConServR Proxy — A Reserved Seat Nobody Claims

What Port 3190 Is

Port 3190 sits in the registered port range (1024–49151). This range is managed by IANA, the Internet Assigned Numbers Authority, which accepts applications from software vendors and standards bodies to reserve port numbers for their products. Unlike the well-known ports below 1024 — which require root privileges to bind and carry the Internet's foundational protocols — registered ports are for ordinary applications that want a consistent, predictable home.

IANA lists port 3190 as assigned to csvr-proxy, described as ConServR Proxy, for both TCP and UDP.¹

The Ghost in the Registry

Here's the problem: ConServR Proxy appears to be a ghost.

The IANA registration exists. The port number is claimed. But search for ConServR and you find nothing — no product page, no documentation, no company, no GitHub repository, no forum posts asking for help with it. Whatever ConServR was, it reserved its place in the registry and then quietly disappeared.

This is not unusual. The registered port space is full of relics. A company registers a port for a product, the product dies or pivots or never ships, and the registration persists indefinitely. IANA doesn't reclaim unused assignments. So port 3190 sits there, officially spoken for, practically unclaimed.

The SANS Internet Storm Center records occasional scanning activity on this port — automated probes sweeping the registered range looking for whatever might be listening.² Nothing about port 3190 specifically; just the background noise of the Internet testing every door.

What This Means for You

If you see traffic on port 3190, it almost certainly isn't ConServR Proxy. It's more likely:

• A custom application that chose this port arbitrarily
• Malware or scanning tools using it as a staging port
• A developer who picked a number in the registered range without checking IANA

The registered range is large enough that many applications treat it as open territory, regardless of what IANA says.

How to See What's Listening

To check if anything on your machine is using port 3190:

macOS / Linux:

# Show the process listening on port 3190
lsof -i :3190

# Or with ss (Linux):
ss -tlnp sport = :3190

Windows:

# Show all listening ports and their process IDs
netstat -ano | findstr :3190

# Then look up the PID
tasklist | findstr <PID>

If nothing is listening, that's expected. Port 3190 is, for most machines, just an empty number.

Why Unassigned (and Half-Assigned) Ports Matter

The registered port range exists to prevent collisions — to ensure that when two applications want a consistent address, they can negotiate one without stepping on each other. The system works when vendors register, ship, and maintain their software. It breaks quietly when they register and disappear.

Port 3190 is a small example of a larger truth: the port registry is a historical document as much as a technical one. It records intentions, not realities. The Internet runs on ports that ignore the registry and ignores ports the registry still claims are busy.