Checking network status in C#

Question

How do I check that I have an open network connection and can contact a specific ip address in c#? I have seen example in VB.Net but they all use the 'My' structure. Thank you.

Solution 1

If you just want to check if the network is up then use:

bool networkUp
    = System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable();

To check a specific interface's status (or other info) use:

NetworkInterface[] networkCards
    = System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces();

To check the status of a remote computer then you'll have to connect to that computer (see other answers)

Solution 2

If you want to monitor for changes in the status, use the System.Net.NetworkInformation.NetworkChange.NetworkAvailabilityChanged event:

NetworkChange.NetworkAvailabilityChanged 
    += new NetworkAvailabilityChangedEventHandler(NetworkChange_NetworkAvailabilityChanged);
_isNetworkOnline = NetworkInterface.GetIsNetworkAvailable();


// ...
void NetworkChange_NetworkAvailabilityChanged(object sender, NetworkAvailabilityEventArgs e)
{
    _isNetworkOnline  = e.IsAvailable;
}

Solution 3

First suggestion (IP connection)

You can try to connect to the IP address using something like:

IPEndPoint ipep = new IPEndPoint(Ipaddress.Parse("IP TO CHECK"), YOUR_PORT_INTEGER);
Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
server.Connect(ipep);

I suggest you to the check code of a "Chat" program. These programs manipulate a lot of IP connections and will give you a good idea of how to check if an IP is available.

Second suggestion (Ping)

You can try to ping. Here is a good tutorial. You will only need to do:

Ping netMon = new Ping();
PingResponse response = netMon.PingHost(hostname, 4);
if (response != null)
{
    ProcessResponse(response);
}

Solution 4

If you're interested in the HTTP status code, the following works fine:

using System;
using System.Net;

class Program {

    static void Main () {
        HttpWebRequest req = WebRequest.Create(
            "http://www.oberon.ch/") as HttpWebRequest;
        HttpWebResponse rsp;
        try {
            rsp = req.GetResponse() as HttpWebResponse;
        } catch (WebException e) {
            if (e.Response is HttpWebResponse) {
                rsp = e.Response as HttpWebResponse;
            } else {
                rsp = null;
            }
        }
        if (rsp != null) {
            Console.WriteLine(rsp.StatusCode);
        }
    }

}

Solution 5

You can check network status using

if(System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable())
{
  //Do your stuffs when network available

}
else
{
 //Do stuffs when network not available

}

View more solutions

Comments

[Brian Clark]

Thanks for the suggestions. The ping class is proving very useful.

[redcalx]

Ping packets (ICMP echo requests) are commonly blocked by firewalls, therefore using this approach to test availability of a server on the other side of a firewall will fail in such a scenario.