package main

import (
	"net"
	"fmt"
)

func listenOn(protocol, port string) {
	fmt.Println("\nAttempting to listen on protocol", protocol, "and port", port)
	l, e := net.Listen(protocol, port)

	if e != nil {
		fmt.Println("FAILURE:", e.Error())
		return
	} else {
		fmt.Println("SUCCESS: Listening on", l.Addr())
		l.Close()
	}

}

func main() {
	listenOn("tcp", ":http") // this will auto-detect and bind to available protocol... 
	listenOn("tcp4", ":http")
	listenOn("tcp6", ":http")
	
}