Delphi ActiveX

Use Public DNS Servers (Google and Cloudfare)

See more DNS Examples

Demonstrates how to use Google and Cloudfare nameservers for all DNS lookups within Chilkat.

Note: This example requires Chilkat v9.5.0.96 or later.

Delphi ActiveX

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
dns: TChilkatDns;
supportsTls: Integer;

begin
// The new Chilkat DNS class is a singleton that allows an applicaton to select 
// the DNS nameservers used throughout Chilkat.

// "singleton" means that all Chilkat DNS object instances work with a single
// copy of internal DNS settings that are application wide.

// Chilkat does DNS lookups internally whenever a domain name is passed to a Chilkat method, or when the domain
// name is part of a URL passed to a Chilkat method.  It could be in HTTP, Ftp2, SSH, IMAP, Socket, etc.

// This exampel will show how to use the Cloudfare and Google DNS servers.
// 
// Google Public DNS:
//   - Primary DNS: 8.8.8.8
//   - Secondary DNS: 8.8.4.4
//   Google Public DNS is known for its speed and reliability. It's operated by Google and is widely used by many internet users.

// Cloudfare Public DNS:
//   - Primary DNS: 1.1.1.1
//   - Secondary DNS: 1.0.0.1
//   Cloudfare Public DNS is also known for its speed and reliability, and is also widely used.

dns := TChilkatDns.Create(Self);

// Indicate our TLS preference:
// 0: No TLS
// 1: Prefer TLS if possible
// 2: Require TLS
dns.TlsPref := 0;

// If you choose "No TLS", then all DNS requests will use UDP, or TCP for those requests with large responses.
// Choosing "No TLS" provides the fastest DNS lookups, and is generally what you're already doing.

// If you choose "Prefer TLS if possible", then Chilkat will use DNS over TLS for those nameservers that
// support TLS.

// If you choose "Require TLS", then Chilkat will ignore nameservers that don't support TLS,
// and all DNS communications will occur over private and secure TLS connections.

// When you specify a nameserver to be used, you'll tell Chilkat whether it supports DNS or not.
// Here' we're setting the nameservers to Google and Cloudfare.
// They both support TLS, but since we set our TLS preference = 0, Chilkat will not use TLS.
// (If we set our TLS preference equal to 1 or 2, then Chilkat will use TLS for Google and Cloudfare DNS.)

// First, make sure we remove all existing nameservers.
dns.RemoveAllNameservers();

// Add the Google and Cloudfare nameservers.
supportsTls := 1;
dns.AddNameserver('1.1.1.1',supportsTls);
dns.AddNameserver('8.8.8.8',supportsTls);
dns.AddNameserver('1.0.0.1',supportsTls);
dns.AddNameserver('8.8.4.4',supportsTls);

// That's it.  Now all DNS lookups in Chilkat will use the above nameservers.
end;