Question 1

What are the three IANA port ranges?

Accepted Answer

The Internet Assigned Numbers Authority (IANA) divides the 16-bit port space (0–65535) into three ranges: Well-Known Ports (0–1023) reserved for system services like HTTP (80) and SSH (22), Registered Ports (1024–49151) assigned to user applications, and Dynamic/Private Ports (49152–65535) used for ephemeral client connections.

Question 2

Should I use a port in the well-known range?

Accepted Answer

On Linux and macOS, binding to a port below 1024 requires root/administrator privileges. For local development, registered ports (1024–49151) or dynamic ports (49152–65535) are usually safer and avoid conflicts with system services.

Question 3

Can I exclude specific ports like 8080 or 3000?

Accepted Answer

Yes. Enter comma-separated ports in the Exclude field and they will be skipped during generation. Useful when you know your dev environment already uses 3000 (Node), 8080 (Java/Tomcat), 5000 (Flask), etc.

Question 4

How random is the result?

Accepted Answer

Every port is drawn from crypto.getRandomValues, the browser's cryptographically secure random source. The output is suitable for unique selection across many runs and for choosing ports that are unlikely to clash with running services.