Two-in-one DNS server with BIND9
This tutorial shows you how to configure BIND9 DNS server to serve an internal network and a external network at the same time with different set of information. To accomplish that goal, a new feature of BIND9 called view is used. As a tutorial it'll walk you through the whole set up, but initial knowledge of BIND and DNS is required, there are plenty of documents that cover that information on the Internet.
1 The problem
It is a typical problem in organizations that are growing that they have to resolve two problems at once:
*To have a DNS server for the internal network of the company because long ago there were already too many computers to remember their IPs1 and even too many computers to maintain a set of host files2.
*To have a DNS server for the external servers, for external clients, etc.
two solve this problems at once become a bigger problem when the growing organization can't supply more resources than one DNS server3.