Если вы используете метод ниже, вы сможете правильно решить
public static bool GetResolvedConnecionIPAddress(string serverNameOrURL, out IPAddress resolvedIPAddress)
{
bool isResolved = false;
IPHostEntry hostEntry = null;
IPAddress resolvIP = null;
try
{
if (!IPAddress.TryParse(serverNameOrURL, out resolvIP))
{
hostEntry = Dns.GetHostEntry(serverNameOrURL);
if (hostEntry != null && hostEntry.AddressList != null && hostEntry.AddressList.Length > 0)
{
if (hostEntry.AddressList.Length == 1)
{
resolvIP = hostEntry.AddressList[0];
isResolved = true;
}
else
{
foreach (IPAddress var in hostEntry.AddressList)
{
if (var.AddressFamily == AddressFamily.InterNetwork)
{
resolvIP = var;
isResolved = true;
break;
}
}
}
}
}
else
{
isResolved = true;
}
}
catch (Exception ex)
{
}
finally
{
resolvedIPAddress = resolvIP;
}
return isResolved;
}