Port 1055: Nifty-Serve — The license gatekeeper

Port 1055 sits in the registered ports range (1024-49151), the middle tier of the port system where applications stake their claims with IANA but don't get the same iron-clad reservation as well-known ports below 1024.

What the Registry Says vs. What Actually Runs

According to IANA, port 1055 is officially assigned to a service called "nifty-serve."¹ You'll find this listed in every port database. But if you actually encounter port 1055 on a network today, it's almost certainly not running nifty-serve.

What you'll find instead: FlexLM license managers.

The Real Port 1055: License Management

By default, the FlexLM service (lmgrd.exe) listens on port 1055.² FlexLM—now part of FlexNet Publisher—is the licensing technology that expensive software uses to control who can run it and how many copies can run simultaneously.

ANSYS, MATLAB, Autodesk products—if you've used professional engineering or scientific software, you've probably talked to a license server. And there's a good chance that server was listening on port 1055.

Here's what happens:

1. You launch your CAD software
2. It immediately connects to the license server on port 1055
3. The license manager (lmgrd) checks: "Do you have permission? Are there enough seats available?"
4. If yes, the vendor daemon (often on a separate dynamic port) hands you a license token
5. Your software runs, periodically checking back in
6. When you close the software, it returns the license

All of this happens in milliseconds. You never see it.

The Vendor Daemon Complication

FlexLM actually uses two ports:

• Port 1055 (or whatever you configure): The main license manager (lmgrd)
• A second port (often dynamic): The vendor daemon (like ansyslmd for ANSYS)

The vendor daemon port changes every time the license server restarts unless you fix it statically. This matters for firewalls. If you're serving licenses across networks, you need to set both ports to known values or your firewall will randomly block license requests.³

Common configuration:

• lmgrd on port 1055
• Vendor daemon on port 1056 (one higher, easy to remember)

Why This Port Matters

Enterprise software licensing is invisible until it breaks. When port 1055 is blocked or the license server goes down, expensive software stops working. Engineers can't run simulations. Designers can't open models. Entire workflows halt.

And because the license check happens at launch, the error messages are often cryptic:

• "Cannot connect to license server"
• "All licenses in use"
• "License checkout failed"

What they really mean: "I tried to talk to port 1055 and something went wrong."

Checking What's Listening

On Linux or macOS:

sudo lsof -i :1055

On Windows:

netstat -ano | findstr :1055

If you see lmgrd or a process with "lm" in the name, you've found a license server.

The Registered Ports Reality

Port 1055 illustrates something important about the registered port range: official assignments don't guarantee actual use.

IANA says this port belongs to nifty-serve. The real world uses it for FlexLM. Both are technically correct. The registration reserves the port number, but there's no enforcement. If your software defaults to 1055 and that works for you, you use 1055.

This is different from well-known ports (0-1023), which are more strictly controlled. Port 80 is HTTP. Port 443 is HTTPS. You don't see random applications claiming those.

But in the registered range? The assignment is more like a suggestion. First come, first served, with IANA keeping a list to reduce conflicts.

Security Note

If you're running a license server, be aware:

• Port 1055 is listening for network connections
• Anyone who can reach that port can query your license status
• Exposed license servers can leak information about what software you're running
• FlexLM has had vulnerabilities in the past⁴

Firewall it. Only allow connections from the networks that need licenses.

The Unassigned Reality

While port 1055 has an official assignment (nifty-serve) and a common use (FlexLM), many ports in the registered range are truly unassigned—no official registration, no common use, just sitting there available for whatever application needs a port.

Those ports matter too. They're the pool that new applications draw from. Every network service needs a port. The registered range provides thousands of options, reducing the chance that two applications on your system will fight over the same number.