Random port generator

    Pick random TCP ports outside the well-known and commonly used ranges.

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    About the random port generator

    Picks random TCP port numbers while avoiding the well-known service ports and, optionally, the ephemeral range the kernel hands out to outbound connections. Saves you discovering a clash after the service is already deployed.

    Frequently asked questions

    Why avoid the ephemeral range?

    Linux allocates 32768 to 60999 for outbound connections. Binding a server there works until the kernel has already handed your number to a client socket, producing an intermittent startup failure.

    How do I check a port is actually free?

    Run ss -tulpn on Linux or netstat -ano on Windows. A number that looks unused here may still be claimed by something running right now.