Port 3156: Indura Collector — A Registered Port Nobody Uses

What Port 3156 Is

Port 3156 sits in the registered ports range (1024–49151). IANA records it as assigned to Indura Collector, registered over both TCP and UDP by Bruce Kosbab.¹ Kosbab subsequently built network monitoring software at Fluke Networks and Netscout — companies whose products scan ports like this one for a living.

There is no public documentation of Indura Collector. No product page, no download, no support forum. The registration exists; the software, for practical purposes, does not.

What the Registered Range Means

Ports 1024–49151 are formally managed by IANA. Any organization or individual can register a port in this range by submitting a request. Registration means the port is recognized as belonging to a specific use — it does not mean the software is in widespread use, actively maintained, or even publicly available.

Thousands of registered ports are assigned to products that have been abandoned, acquired, or simply never shipped. Port 3156 is one of them. The name is in the table. The table doesn't know the software is gone.

The Gaming Overlap

Port 3156 also falls inside the UDP range 3074–3174 used by Tom Clancy's Rainbow Six: Vegas for online multiplayer.² Routers port-forwarded to this range for gaming would pass traffic through 3156 without distinguishing it from any neighbor in the range.

This is not a conflict — it's just how port ranges work in practice. Game developers pick a block, registrations exist within that block, and the two coexist without issue because neither is claiming exclusive control at the packet level.

How to Check What's Listening on Port 3156

If you see traffic on port 3156 and want to know the source:

On Linux or macOS:

# Show the process listening on port 3156
sudo lsof -i :3156

# Or with ss (Linux):
sudo ss -tlnp sport = :3156

On Windows:

# Show listening ports with process IDs
netstat -ano | findstr :3156

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

If nothing appears, nothing is listening. If something appears, it is almost certainly not Indura Collector.

Why Unassigned-in-Practice Ports Matter

Scanners, firewalls, and intrusion detection systems treat unexpected traffic on any port as a signal. A process quietly opening port 3156 won't be recognized by name — there is no well-known service to match it against. That obscurity cuts both ways: it means legitimate software using this port gets no benefit of the doubt, and malicious software using it gets no automatic flag.

The registered ports range is full of these quiet numbers. They were claimed, then forgotten. They are not dangerous, but they are not meaningless either — they are the gaps between the landmarks, and gaps are where surprises live.