public static void DisplayDnsAddresses()
{
    NetworkInterface[] adapters  = NetworkInterface.GetAllNetworkInterfaces();
    foreach (NetworkInterface adapter in adapters)
    {

        IPInterfaceProperties adapterProperties = adapter.GetIPProperties();
        IPAddressCollection dnsServers = adapterProperties.DnsAddresses;
        if (dnsServers.Count > 0)
        {
            Console.WriteLine(adapter.Description);
            foreach (IPAddress dns in dnsServers)
            {
                Console.WriteLine("  DNS Servers ............................. : {0}", 
                    dns.ToString());
            }
            Console.WriteLine();
        }
    }
}