Unity check internet connection availability

Question

I am porting our game to Unity, and need some help regarding internet connectivity check in Unity. Official Unity Documentation says 'do not use Application.internetReachability. So i am confused which code will work here. Didn't find any prominent solution in any forum. I want to check whether wi-fi or GPRS is on or not which should work for iOS and Android. Thanks in advance.

Answer 1

Solution

Application.internetReachability is what you need. In conjunction with Ping, probably.

Here's an example:

using UnityEngine;

public class InternetChecker : MonoBehaviour
{
    private const bool allowCarrierDataNetwork = false;
    private const string pingAddress = "8.8.8.8"; // Google Public DNS server
    private const float waitingTime = 2.0f;

    private Ping ping;
    private float pingStartTime;

    public void Start()
    {
        bool internetPossiblyAvailable;
        switch (Application.internetReachability)
        {
            case NetworkReachability.ReachableViaLocalAreaNetwork:
                internetPossiblyAvailable = true;
                break;
            case NetworkReachability.ReachableViaCarrierDataNetwork:
                internetPossiblyAvailable = allowCarrierDataNetwork;
                break;
            default:
                internetPossiblyAvailable = false;
                break;
        }
        if (!internetPossiblyAvailable)
        {
            InternetIsNotAvailable();
            return;
        }
        ping = new Ping(pingAddress);
        pingStartTime = Time.time;
    }

    public void Update()
    {
        if (ping != null)
        {
            bool stopCheck = true;
            if (ping.isDone)
            {
                if (ping.time >= 0)
                    InternetAvailable();
                else
                    InternetIsNotAvailable();
            }
            else if (Time.time - pingStartTime < waitingTime)
                stopCheck = false;
            else
                InternetIsNotAvailable();
            if (stopCheck)
                ping = null;
        }
    }

    private void InternetIsNotAvailable()
    {
        Debug.Log("No Internet :(");
    }

    private void InternetAvailable()
    {
        Debug.Log("Internet is available! ;)");
    }
}

Things to note

1. Unity's ping doesn't do any domain name resolutions, i.e. it only accepts IP addresses. So, if some player has Internet access but has some DNS problems, the method will say that he has Internet.
2. It's only a ping check. Don't expect it to be 100% accurate. In some rare cases it will provide you with false information.

Answer 2

What I do is Network.TestConnection which tests for connectivity, whether or not it can be a server, and whether or not NAT punch through can be used successfully.

This is the sample code they have given us. If the result is ConnectionTesterStatus.Error, chances are there is no internet access.

var testStatus = "Testing network connection capabilities.";
var testMessage = "Test in progress";
var shouldEnableNatMessage : String = "";
var doneTesting = false;
var probingPublicIP = false;
var serverPort = 9999;
var connectionTestResult = ConnectionTesterStatus.Undetermined;

// Indicates if the useNat parameter be enabled when starting a server
var useNat = false;

function OnGUI() {
    GUILayout.Label("Current Status: " + testStatus);
    GUILayout.Label("Test result : " + testMessage);
    GUILayout.Label(shouldEnableNatMessage);
    if (!doneTesting)
        TestConnection();
}

function TestConnection() {
    // Start/Poll the connection test, report the results in a label and 
    // react to the results accordingly
    connectionTestResult = Network.TestConnection();
    switch (connectionTestResult) {
        case ConnectionTesterStatus.Error: 
            testMessage = "Problem determining NAT capabilities";
            doneTesting = true;
            break;

        case ConnectionTesterStatus.Undetermined: 
            testMessage = "Undetermined NAT capabilities";
            doneTesting = false;
            break;

        case ConnectionTesterStatus.PublicIPIsConnectable:
            testMessage = "Directly connectable public IP address.";
            useNat = false;
            doneTesting = true;
            break;

        // This case is a bit special as we now need to check if we can 
        // circumvent the blocking by using NAT punchthrough
        case ConnectionTesterStatus.PublicIPPortBlocked:
            testMessage = "Non-connectable public IP address (port " +
                serverPort +" blocked), running a server is impossible.";
            useNat = false;
            // If no NAT punchthrough test has been performed on this public 
            // IP, force a test
            if (!probingPublicIP) {
                connectionTestResult = Network.TestConnectionNAT();
                probingPublicIP = true;
                testStatus = "Testing if blocked public IP can be circumvented";
                timer = Time.time + 10;
            }
            // NAT punchthrough test was performed but we still get blocked
            else if (Time.time > timer) {
                probingPublicIP = false;        // reset
                useNat = true;
                doneTesting = true;
            }
            break;
        case ConnectionTesterStatus.PublicIPNoServerStarted:
            testMessage = "Public IP address but server not initialized, "+
                "it must be started to check server accessibility. Restart "+
                "connection test when ready.";
            break;

        case ConnectionTesterStatus.LimitedNATPunchthroughPortRestricted:
            testMessage = "Limited NAT punchthrough capabilities. Cannot "+
                "connect to all types of NAT servers. Running a server "+
                "is ill advised as not everyone can connect.";
            useNat = true;
            doneTesting = true;
            break;

        case ConnectionTesterStatus.LimitedNATPunchthroughSymmetric:
            testMessage = "Limited NAT punchthrough capabilities. Cannot "+
                "connect to all types of NAT servers. Running a server "+
                "is ill advised as not everyone can connect.";
            useNat = true;
            doneTesting = true;
            break;

        case ConnectionTesterStatus.NATpunchthroughAddressRestrictedCone:
        case ConnectionTesterStatus.NATpunchthroughFullCone:
            testMessage = "NAT punchthrough capable. Can connect to all "+
                "servers and receive connections from all clients. Enabling "+
                "NAT punchthrough functionality.";
            useNat = true;
            doneTesting = true;
            break;

        default: 
            testMessage = "Error in test routine, got " + connectionTestResult;
    }
    if (doneTesting) {
        if (useNat)
            shouldEnableNatMessage = "When starting a server the NAT "+
                "punchthrough feature should be enabled (useNat parameter)";
        else
            shouldEnableNatMessage = "NAT punchthrough not needed";
        testStatus = "Done testing";
    }
}