Port 3644: SSOWatch — The Credential Watcher

What Port 3644 Does

Port 3644 belongs to SSOWatch, a component of Evidian's Enterprise Single Sign-On product.¹ The service runs as an agent on user workstations, watching for application login prompts and automatically supplying credentials — so employees can open applications without typing passwords.

The name is entirely literal. SSOWatch watches. When a known application presents a login screen, the agent intercepts it and fills in the appropriate credentials from a central store. The user gets seamless access; the IT department gets centralized password control and audit trails.

Evidian is a French cybersecurity company (now part of the Atos group) that has built enterprise identity management products since the late 1990s.²

The Registered Port Range

Port 3644 sits in the registered ports range (1024–49151). These ports are assigned by IANA to specific services upon request — they're not reserved like well-known ports (0–1023), but they're documented. Any organization can run any service on a registered port; the assignment is a declaration of intent, not a technical lock.

In practice, most registered ports only matter in the networks that run the associated software. If your organization doesn't use Evidian Enterprise SSO, port 3644 is silent on your machines.

Autodesk Backburner

Port 3644 also shows up in documentation for Autodesk Backburner, a render farm management system used with 3ds Max, Maya, and other Autodesk products.³ Backburner distributes rendering tasks across multiple machines, and various sources cite 3644 as one of its communication ports — though Backburner's primary documented ports are 3233 and 3234.

This is a common situation in registered port space: a formally assigned service and an informal convention for an entirely different application sharing the same number. If you see traffic on port 3644 in a visual effects or animation studio, Backburner is the more likely explanation than SSOWatch.

How to Check What's Using It

To see if anything is listening on port 3644 on your machine:

macOS / Linux:

lsof -i :3644

Windows:

netstat -ano | findstr :3644

Cross-platform with nmap:

nmap -p 3644 localhost

If nothing is listening, the port is closed — which is the expected state on any machine not running Evidian Enterprise SSO or Autodesk Backburner.

Why Unassigned-Looking Ports Matter

Most registered ports are invisible most of the time. They only matter in the specific environments that run their assigned software. Port 3644 is quiet everywhere except in the enterprise networks that deployed Evidian's SSO, and in the render farms where artists wait for frames to finish.

That invisibility is the point. A well-functioning port does its job without calling attention to itself.