Port 3607: Precise I3 — A Registered Port Nobody Knocks On

What Port 3607 Is

Port 3607 is a registered port, officially assigned by IANA to Precise I3 — a product from Precise Software Solutions, an Israeli-American company that built application performance management (APM) software in the early 2000s.¹

The IANA assignment covers both TCP and UDP. It was registered in September 2002 by Tomer Shain of Precise Software Solutions.²

What Precise I3 Was

Precise I3 was an enterprise monitoring platform. It watched how applications behaved across the full stack — databases, servers, storage, middleware — and tried to pinpoint the root cause of slowdowns before users noticed them. The name "I3" stood for the three things it promised to deliver: insight, intelligence, and intervention.

In the early 2000s, APM was a serious problem. Applications were growing more complex, databases were getting hammered, and operations teams had no good way to see what was causing degradation. Precise built a product that bridged that gap.

The company was acquired by Veritas in 2004, then the technology eventually moved to Idera, where pieces of it survive today under the broader application performance portfolio.³

Port 3607 outlasted all of it.

What This Range Means

Port 3607 sits in the registered port range (1024–49151). These ports are not reserved for system services — they are claimed by software vendors who register them with IANA to avoid collisions with other products.⁴

Registering a port costs nothing but a form. The result is a permanent record in the IANA registry, regardless of whether the product still ships, still works, or still exists. Precise registered port 3607 in 2002. The product evolved, the company was sold, the company was sold again. The port registration has remained unchanged.

Will You Ever See This Port?

Almost certainly not. Unless you are running a legacy Precise Software installation from the early-to-mid 2000s, port 3607 will be silent on every machine you own.

If you see something listening on this port and you do not recognize it, that warrants attention. It could be:

• Legacy enterprise monitoring software (genuine, but rare)
• A misconfigured or mislabeled application that chose this port arbitrarily
• Something you should investigate

How to Check What Is Listening

On macOS or Linux:

sudo lsof -i :3607

or

ss -tlnp | grep 3607

On Windows:

netstat -ano | findstr :3607

Then take the process ID from the output and look it up:

# Linux/macOS
ps aux | grep <PID>

# Windows
tasklist | findstr <PID>

Why Ghost Ports Exist

Every major software product from the 2000s claimed a port. Most of those products have been retired, replaced, or absorbed. The port registry still holds their names — a graveyard of registered claims that no traffic will ever visit.

This is not a flaw in how IANA manages the registry. It is an honest record of what the Internet looked like when enterprise software was sprawling, acquisitions were frequent, and every product wanted its own door.

Port 3607 is one of thousands of ports in this category: assigned, once meaningful, now quiet.