How can I deal with split horizon DNS on the road warrior side of a VPN?
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I want to set up a VPN for the following scenario:
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I have a MAIN site with LAN only services.
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The MAIN site uses Host Overrides in the DNS Resolver to give hostnames to LAN only services.
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I have a REMOTE user that I'd like to connect to the MAIN site as an OpenVPN road warrior.
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The REMOTE user wants to access services using the same hostnames as the MAIN site.
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The remote site has a significantly faster internet connection than the MAIN site. IE: Redirect Gateway is not an option.
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The remote site has services using split horizon DNS.
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The only device I control at the REMOTE site is a laptop for the road warrior.
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The road warrior at the REMOTE site connects using OpenVPN GUI.
I have an OpenVPN (Remote Access SSL / TLS) server that:
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Does NOT use Redirect Gateway.
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Pushes the LAN as an IPv4 Local network.
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Pushes the firewalls domain as a DNS Default Domain.
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Pushes the LAN IP as a DNS Server.
This does everything I'd like except it breaks the REMOTE site's split horizon DNS. For example, without being connected to the VPN, www.example.com resolves to a local IP. After connecting to the VPN www.example.com resolves to the external IP.
Are there any tricks I can use so only DNS lookups within the DNS Default Domain end up using the MAIN site's DNS Resolver? Is there a better config for what I'm trying to accomplish?
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