Port 3525: EIS Server — Registered, Forgotten

What Port 3525 Is

Port 3525 sits in the registered ports range (1024–49151), which means it's not a blank slate — the Internet Assigned Numbers Authority has an entry for it. The service name is eisport. The description is "EIS Server port."¹

That's about where the trail goes cold.

The Registration

In June 2002, someone named Paul Kraus registered port 3525 with IANA using a @veritas.com email address.¹ Veritas Software was a serious enterprise company in that era — the company behind NetBackup, Volume Manager, and Backup Exec, products that ran on the storage backbone of large organizations. When they registered a port, it was for real infrastructure.

EIS almost certainly stood for something — Enterprise Information Server, perhaps, or an internal product name. But the software appears to have been discontinued, acquired, or folded into something else before it left much of a mark on the public record. The IANA registration outlived whatever it was built for.

What This Means in Practice

The port is registered but dormant. You're unlikely to encounter legitimate EIS Server traffic. If you see something listening on port 3525 on your system, it's almost certainly something else — an application that chose the port arbitrarily, a piece of malware that picked a quiet number, or a development service that grabbed a random high port.

To check what's using port 3525 on your system:

# Linux / macOS
ss -tlnp | grep 3525
lsof -i :3525

# Windows
netstat -ano | findstr :3525

The PID you get back will tell you which process is listening. Cross-reference with ps or Task Manager to identify it.

Why Ghost Registrations Exist

The IANA registry has tens of thousands of entries. Some are living, critical infrastructure — SSH on 22, HTTPS on 443. Others are registrations from products that didn't survive, companies that got acquired, protocols that never reached adoption.

Port 3525 is in that second category. The registration was made in good faith for what was presumably a real product. The product disappeared. The port stayed registered, quietly sitting in the IANA database as a 23-year-old reminder that software doesn't always outlive its paperwork.

This is actually useful information: registered doesn't mean active. The registered ports range is a map of what software projects intended to use, not necessarily what's running right now.