A caching name server can be beneficial in a number of situations. First, because it brings name service closer to the user, performance of all name-based services will likely be improved. Also, in secured environments with a strict firewall implementation, it can be used to allow local clients to obtain name service without having to pierce the firewall for all users. Only the local caching DNS server must have access to outside name servers. Finally, it provides a simple mechanism for providing a private name space to local users, by allowing users to obtain all name service from the local caching name server which also acts as a master name server for the local network name space.
A caching name server is perhaps the simplest type of name server to configure, and Webmin makes the configuration even easier. Because caching is a core part of how DNS scales, it is an automatic part of any BIND configuration. All that is left for us to do is allow Webmin to create our initial configuration files, and alter a couple of options in the configuration.
Initializing the named.conf
When first opening the Webmin BIND DNS Server module, you'll be given a few choices about how to generate the initial configuration files. The ideal choice is to allow Webmin to initialize your configuration, and download the root name server list. If you are not currently connected to the network you can choose to use the root name server list file that is included in the Webmin distribution.
After Webmin has completed the download, and initialized your files, click on the Forwarding and Transfers icon. Add the primary and secondary name server addresses provided by your ISP to the field labeled Servers to forward queries to. Then select Yes for the option Lookup directly if no response from forwarder. Click Save.
Believe it or not, your configuration is finished. Simply click on the Start BIND button, and point your client workstations to the IP of your server for their primary name server, and test it out. Check the later section on troubleshooting BIND if problems arise.