I've got some code here that works great on IPv4 machines, but on our build server (an IPv6) it fails. In a nutshell:
IPHostEntry ipHostEntry = Dns.GetHostEntry(string.Empty);
The documentation for GetHostEntry says that passing in string.Empty will get you the IPv4 address of the localhost. This is what I want. The problem is that it's returning the string "::1:" on our IPv6 machine, which I believe is the IPv6 address.
Pinging the machine from any other IPv4 machine gives a good IPv4 address... and doing a "ping -4 machinename" from itself gives the correct IPv4 address.... but pinging it regularly from itself gives "::1:".
How can I get the IPv4 for this machine, from itself?
To find all valid address list this is the code I have used
public static IEnumerable<string> GetAddresses()
{
var host = Dns.GetHostEntry(Dns.GetHostName());
return (from ip in host.AddressList where ip.AddressFamily == AddressFamily.lo select ip.ToString()).ToList();
}
public static string GetIPAddress(string hostname)
{
IPHostEntry host;
host = Dns.GetHostEntry(hostname);
foreach (IPAddress ip in host.AddressList)
{
if (ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
{
//System.Diagnostics.Debug.WriteLine("LocalIPadress: " + ip);
return ip.ToString();
}
}
return string.Empty;
}
IPHostEntry ipHostInfo = Dns.GetHostEntry(serverName);
IPAddress ipAddress = ipHostInfo.AddressList
.FirstOrDefault(a => a.AddressFamily == AddressFamily.InterNetwork);
To find all local IPv4 addresses:
IPAddress[] ipv4Addresses = Array.FindAll(
Dns.GetHostEntry(string.Empty).AddressList,
a => a.AddressFamily == AddressFamily.InterNetwork);
or use Array.Find
or Array.FindLast
if you just want one.
IPv6
lblIP.Text = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName).AddressList(0).ToString()
IPv4
lblIP.Text = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName).AddressList(1).ToString()
public Form1()
{
InitializeComponent();
string myHost = System.Net.Dns.GetHostName();
string myIP = null;
for (int i = 0; i <= System.Net.Dns.GetHostEntry(myHost).AddressList.Length - 1; i++)
{
if (System.Net.Dns.GetHostEntry(myHost).AddressList[i].IsIPv6LinkLocal == false)
{
myIP = System.Net.Dns.GetHostEntry(myHost).AddressList[i].ToString();
}
}
}
Declare myIP and myHost in public Variable and use in any function of the form.
Source: Stackoverflow.com