Objective-C

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.

Objective-C

#import <CkoDns.h>

// 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.

CkoDns *dns = [[CkoDns alloc] init];

// Indicate our TLS preference:
// 0: No TLS
// 1: Prefer TLS if possible
// 2: Require TLS
dns.TlsPref = [NSNumber numberWithInt: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.
BOOL supportsTls = YES;
[dns AddNameserver: @"1.1.1.1" supportsTls: supportsTls];
[dns AddNameserver: @"8.8.8.8" supportsTls: supportsTls];
[dns AddNameserver: @"1.0.0.1" supportsTls: supportsTls];
[dns AddNameserver: @"8.8.4.4" supportsTls: supportsTls];

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