(PowerBuilder) Use Public DNS Servers (Google and Cloudfare)

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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.

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integer li_rc
oleobject loo_Dns
integer li_SupportsTls

// 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.

loo_Dns = create oleobject
// Use "Chilkat_9_5_0.Dns" for versions of Chilkat < 10.0.0
li_rc = loo_Dns.ConnectToNewObject("Chilkat.Dns")
if li_rc < 0 then
    destroy loo_Dns
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// Indicate our TLS preference:
// 0: No TLS
// 1: Prefer TLS if possible
// 2: Require TLS
loo_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.
loo_Dns.RemoveAllNameservers()

// Add the Google and Cloudfare nameservers.
li_SupportsTls = 1
loo_Dns.AddNameserver("1.1.1.1",li_SupportsTls)
loo_Dns.AddNameserver("8.8.8.8",li_SupportsTls)
loo_Dns.AddNameserver("1.0.0.1",li_SupportsTls)
loo_Dns.AddNameserver("8.8.4.4",li_SupportsTls)

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


destroy loo_Dns