Local DNS server

Solution 1:

This is all about DNS resolution, and forwarding. :)

• Setup an internal DNS server.
• Set the DNS server to forward all unknown requests to an outside DNS server (like Google's or your ISPs).
• Setup DHCP to give LAN clients the internal DNS server as their DNS server setting.
• In the internal DNS, setup a domain zone (domain.com) or host-specific zones (machine.domain.com) to cover the hosts/domain in question, using their internal IP addresses.

Now when the LAN clients make a DNS request it will ask the internal DNS server for the IP. If it has that host/domain entry, it will resolve and return the local IP, if it doesn't recognize the requested host/domain it will be forwarded to the public DNS for resolution.