Added in 1.9.0


Returns $true if the specified port number is not in use, otherwise $false.


N - The port number to check.
[ipaddress] - If specified, only the interface with that IP address is checked for used ports, otherwise all active interfaces are checked. An adapter name can also be used instead of an IP address.


; Check if port 4242 is free.
//echo -ag Port 4242 is $iif($portfree(4242), open, not open)