Unity Script Reference – Network.HavePublicAddress

Check if this machine has a public IP address.

It checks all the network interfaces for IPv4 public addresses and returns true if one address is found.

JavaScripts

function OnGUI() {
if (GUILayout.Button ("Start Server")) {
// Use NAT punchthrough if no public IP present
var useNat = !Network.HavePublicAddress();
Network.InitializeServer(32, 25002, useNat);
MasterServer.RegisterHost("MyUniqueGameType",
"JohnDoes game", "l33t game for all");
}
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void OnGUI() {
if (GUILayout.Button("Start Server")) {
bool useNat = !Network.HavePublicAddress();
Network.InitializeServer(32, 25002, useNat);
MasterServer.RegisterHost("MyUniqueGameType", "JohnDoes game", "l33t game for all");
}
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def OnGUI():
if GUILayout.Button('Start Server'):
useNat as bool = (not Network.HavePublicAddress())
Network.InitializeServer(32, 25002, useNat)
MasterServer.RegisterHost('MyUniqueGameType', 'JohnDoes game', 'l33t game for all')