B4X

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.

B4X

'  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.

Dim dns As ChilkatDns
dns.Initialize("dns")

'  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.
Dim supportsTls As Boolean = True
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.