Get external IP address (nat-pmp)

eip.go

package main

import (
	"fmt"
	"log"

	"github.com/jackpal/gateway"
	natpmp "github.com/jackpal/go-nat-pmp"
)

func main() {
	gatewayIP, err := gateway.DiscoverGateway()
	if err != nil {
		log.Fatal(err)
	}

	client := natpmp.NewClient(gatewayIP)
	response, err := client.GetExternalAddress()
	if err != nil {
		log.Fatal(err)
	}

	ip := response.ExternalIPAddress
	fmt.Printf("%d.%d.%d.%d\n", ip[0], ip[1], ip[2], ip[3])
}