private void Button_Click_6(object sender, RoutedEventArgs e) { int port = 8080; string ip = "127.0.0.1"; TcpClient client = new TcpClient(ip, port); string[] hostNames = { "www.microsoft.com", "www.apple.com", "www.google.com", "www.ibm.com", "cisco.netacad.net", "www.oracle.com", "www.nokia.com", "www.hp.com", "www.dell.com", "www.samsung.com", "www.toshiba.com","www.siemens.com", "www.amazon.com", "www.sony.com", "www.canon.com", "www.alcatellucent.com", "www.acer.com", "www.motorola.com" }; ; IPAddress[] ipAddresses; var permissionState = System.Security.Permissions.PermissionState.Unrestricted; DnsPermission dnsPermission = new DnsPermission(permissionState); dnsPermission.PermitOnly(); for (var index = 0; index < hostNames.Length; index++) { string hN = hostNames[index]; ipAddresses = Dns.GetHostAddresses(hN); ipAddress.Text += hN + " => \n" + ipAddresses.ToString() + "\n"; } }