Network.connectionTesterPort  

function ResetIP() {
    Network.connectionTesterIP = "127.0.0.1";
    Network.connectionTesterPort = 10000;
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void ResetIP() {
        Network.connectionTesterIP = "127.0.0.1";
        Network.connectionTesterPort = 10000;
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def ResetIP():
        Network.connectionTesterIP = '127.0.0.1'
        Network.connectionTesterPort = 10000