Port 2631: Sitara Dir — A Registered Port for a Defunct Product

What Port 2631 Is

Port 2631 is a registered port — officially assigned by IANA to a service called sitaradir (Sitara Dir) for both TCP and UDP.¹

The registrant was Sitara Networks, a Waltham, Massachusetts company founded in 1997 that built Quality of Service appliances for enterprise networks. Their gear managed bandwidth, enforced traffic policies, and monitored application performance. sitaradir was a directory service component of the Sitara platform, used for managing and discovering Sitara devices across a network.

Sitara Networks was acquired by Converged Access in 2004.² The platform it was registered for is gone.

What "Registered" Actually Means Here

There are 65,535 ports. IANA divides them into three ranges:

• Well-known ports (0–1023): Reserved for foundational Internet services — HTTP, SSH, DNS, SMTP. Requires IETF review to assign.
• Registered ports (1024–49151): Available for assignment upon application. A company or developer registers a port for a specific service, and IANA records it. This is where port 2631 lives.
• Dynamic/ephemeral ports (49152–65535): Unregistered, used temporarily by clients for outbound connections.

"Registered" does not mean "important" or "in widespread use." It means someone filed the paperwork. When the company or product disappears, the registration stays — the port is frozen in IANA's records, technically spoken for by software that no longer ships.³

Is Anything Else Using It?

No significant unofficial use of port 2631 has been documented. It's quiet.

When you see a registered-but-dormant port like this in the wild, it's usually one of three things:

1. Old enterprise software that still ships the Sitara-era configuration
2. A scanner probe — security tools scanning common registered ports
3. Coincidental use by an internal application that picked a number without checking the registry

How to Check What's Listening

If you see traffic on port 2631 and want to know what it is:

On Linux/macOS:

sudo ss -tlnp | grep 2631
sudo lsof -i :2631

On Windows:

netstat -ano | findstr :2631

Match the PID from those results to a process in Task Manager or ps aux. Something will own it — the question is whether it's legitimate software or something you didn't knowingly install.

Why Ghost Ports Matter

IANA's registry contains hundreds of ports like 2631: assigned decades ago for products that no longer exist, to companies that were acquired or dissolved. These ports aren't dangerous by themselves. But they're a useful reminder that port numbers are not inherently meaningful — the registry is a record of intent, not a guarantee of activity.

The ports that matter are the ones where something is actually listening.