Port 1155: Network File Access — A registered port for a database you've probably never heard of

What Port 1155 Is

Port 1155 is officially registered with IANA for Network File Access (NFA)—a protocol designed for remote access to Rocket UniData database files over a network.¹² The registration covers both TCP and UDP protocols and lists James Powell from Unidata as the contact.³

If you've never heard of UniData, you're not alone. It's a MultiValue database management system used primarily in vertical market applications—the kind of enterprise software that runs quietly in specific industries for decades.⁴

What NFA Does

Network File Access allows remote systems to access UniData database files across a network. Think of it as a specialized file-sharing protocol, but instead of sharing documents or media files, it's sharing database files between UniData instances.⁵

The protocol includes features like distributed database access, data pointers that link multiple UniData systems together, and network-based file operations specific to the MultiValue database model.⁵

The Reality of This Port

Here's the thing: you're extremely unlikely to encounter traffic on port 1155 unless you're working in an environment that specifically uses Rocket UniData databases. This is a registered port (in the 1024-49151 range), meaning someone requested it from IANA and received an official assignment.

But official assignment doesn't mean widespread use. The Internet is full of ports like this—registered decades ago for specific commercial products, still sitting in the registry, technically claimed but practically invisible to most network administrators.

Why This Port Matters (Even If You Never Use It)

Port 1155 represents something important about how the Internet's port system works: persistence. Once a port is registered, it stays registered. The protocol might fade into obscurity, the company might be acquired, the software might be legacy—but the port assignment remains.

This creates a historical record. Looking through IANA's port registry is like reading an archaeological record of networking history—layers upon layers of protocols, some thriving, most forgotten, all still technically allocated.

Checking What's on Port 1155

If you want to see whether anything is actually listening on port 1155 on your system:

On Linux or macOS:

sudo lsof -i :1155
# or
sudo netstat -tulpn | grep 1155

On Windows:

netstat -ano | findstr :1155

Chances are you'll see nothing. But if you do see something listening on 1155 and you're not running UniData, that's worth investigating—it could be legitimate software using an unassigned port, or it could be something unauthorized.

The Registered Port Range

Port 1155 falls in the registered ports range (1024-49151). These ports are assigned by IANA for specific services, but the assignments aren't enforced. Anyone can run any service on any registered port—the registry is more about preventing conflicts than enforcing usage.

The registration process exists so that if two different software vendors both want to use port 5000, there's a system to say "actually, this one is already claimed." It reduces collisions in the wild, but it doesn't prevent them.

Related Ports

If you're interested in database-specific ports, here are some that actually see regular use:

• Port 3306 — MySQL database default port
• Port 5432 — PostgreSQL database default port
• Port 1521 — Oracle database default port
• Port 1433 — Microsoft SQL Server default port

Unlike port 1155, these ports carry traffic on networks worldwide every second.