(SQL Server) 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.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    -- 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.

    DECLARE @dns int
    -- Use "Chilkat_9_5_0.Dns" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Dns', @dns OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Indicate our TLS preference:
    -- 0: No TLS
    -- 1: Prefer TLS if possible
    -- 2: Require TLS
    EXEC sp_OASetProperty @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.
    EXEC sp_OAMethod @dns, 'RemoveAllNameservers', NULL

    -- Add the Google and Cloudfare nameservers.
    DECLARE @supportsTls int
    SELECT @supportsTls = 1
    EXEC sp_OAMethod @dns, 'AddNameserver', NULL, '1.1.1.1', @supportsTls
    EXEC sp_OAMethod @dns, 'AddNameserver', NULL, '8.8.8.8', @supportsTls
    EXEC sp_OAMethod @dns, 'AddNameserver', NULL, '1.0.0.1', @supportsTls
    EXEC sp_OAMethod @dns, 'AddNameserver', NULL, '8.8.4.4', @supportsTls

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

    EXEC @hr = sp_OADestroy @dns


END
GO