How to get local machine ip address using C#?

Question

_{Tuesday, October 4, 2011 9:01 AM}

e.g. FooA runs at ComputerA, how can FooA know ComputerA ip address (not localhost/127.0.0.1)?  

Any sample would be appreciated.

Thanks.

All replies (9)

_{Tuesday, October 4, 2011 9:09 AM ✅Answered}

     Console.WriteLine(Dns.GetHostName());
        IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());
        foreach (IPAddress addr in localIPs)
        {
            Console.WriteLine(addr);
        }

_{Tuesday, October 4, 2011 9:13 AM ✅Answered | 2 votes}

System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces()

returns all your network interfaces.

Call GetIPProperties() on each one to get the properties of the interface, including its UnicastAddresses and MulticastAddresses.

_{Tuesday, October 4, 2011 9:39 AM ✅Answered | 3 votes}

Console.WriteLine(Dns.GetHostName());
        IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());
        foreach (IPAddress addr in localIPs)
        {
            if (addr.AddressFamily == AddressFamily.InterNetwork)
            {
                Console.WriteLine(addr);
            }
        }

_{Tuesday, October 4, 2011 9:06 AM | 2 votes}

The only way to know your public IP is to ask someone else to tell you; this code may help you:

 public string getPublicIP() {
string direction;
WebRequest request = WebRequest.Create("http://checkip.dyndns.org/");
WebResponse response = request.GetResponse();
 StreamReader stream = new StreamReader(response.GetResponseStream());
 direction = stream.ReadToEnd();
stream.Close();
response.Close(); //Search for the ip in the html
int first = direction.IndexOf("Address: ") + 9;
int last = direction.LastIndexOf("");
direction = direction.Substring(first, last - first);
return direction;
}

_{Tuesday, October 4, 2011 9:30 AM}

The returned array including IPv6, e.g. the following,

Dns.GetHostAddresses(Dns.GetHostName())

{System.Net.IPAddress[4]}

[0]: {fe80::1111:3333:2222:d08f%11}

[1]: {fe80::1234:11.178.192.99%12}

[2]: {2099:4898:0:fff:0:1234:11.178.192.99}

[3]: {11.178.192.99}

Is there a way only returning ipv4? or can I assume the last one is always the ipv4? Or even there is another best approach?

Thanks.

_{Tuesday, October 4, 2011 9:50 AM | 6 votes}

Thanks all.

This also works,

IPAddress ip = Dns.GetHostAddresses(Dns.GetHostName()).Where(address => address.AddressFamily == AddressFamily.InterNetwork).First();

Thanks. 

_{Wednesday, October 5, 2011 6:33 AM}

Thank you all for your active participation in the MSDN forum!

Hi Wood,
Welcome to the MSDN forum!

If you have any questions in the future programming, you are welcome to post them in the forum.

Have a nice day!Yoyo Jiang[MSFT]
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_{Thursday, July 13, 2017 1:02 PM}

Thanks

_{Saturday, April 20, 2019 11:31 PM}

Sorry. This should is not the best answer. This gives you a list of addresses with no clue as to what they are. If you are looking for your local network address, you will not be able to identify it from this list. Not useful.