A master DNS server contains the zone files which dictate the IP addresses and hostnames for a zone. A slave DNS server contains the same information, but must obtain its information from a master DNS server. For example, when a primary name server starts, it reads the zone information from files on the disk. However, when a slave name server starts, it asks the primary for the information.

You can run a DNS cache on your computer. This will speed up the process of looking up domain names when browsing. The difference is about 30-60 ms for me. Multiply that difference by the number of websites you visit a day for an approximate estimate of the speed improvement. Of course, all this would be worth it if it weren’t for the fact that setting this up is way too easy.

...it's estimated that more than 50,000 new domain names are registered each day. The Domain Name Service (DNS, also often referred to as the Domain Name System) was created to help solve this problem. DNS is essentially a huge conga line of servers (called name servers) snaking through the Internet. For any computer connected to the Net, a given DNS server can provide you with that computer's host name and IP address information itself, or the server knows how to find other name servers that will have that information.

In this story we give a general overview of the DNS system, how it's implemented on Linux, and how to configure it. We describe the files that hold the configuration information and host database and where they're located. Sample configuration files are also included to get you started with your own DNS setup.

"OpenDNS runs a really big, smart cache, so every OpenDNS user benefits from the activities of the broader OpenDNS user base," says Allison Rhodes, community manager of OpenDNS. She says OpenDNS runs a high-performance network that is geographically distributed and serviced by several redundant connections.

Understanding the mechanics behind DNS is important when securing your DNS server. DNS is robust and full featured; understanding what resources each DNS action requires will allow administrators to disable unnecessary features, therefore achieving a minimalist and secure DNS server. This section reviews the basics of DNS mechanics. Domain name information is stored in flat text files called zone files. User requests and server replies are simple text-file searches and take very few system resources. Some newer DNS technologies allow for write access to update record data and other configurations remotely. However, unless write access is explicitly enabled, from an end user perspective DNS should be referred to as a read-only service. DNS is mechanically broken up into records, servers, and their respective chains of authority from the root servers...

People who use the Web these days have probably developed extremely good "mental filters" that allow them to ignore the blizzard of banner ads, pop-ups, and other chaff, which seem to make up the majority of the content on many major Web sites. But one day the flashing, jumping, singing, whiz-bangy-ness of it all got to me and I decided to do something to reduce the amount of visual noise I had to deal with when surfing the Web. The bonus was that once I was able to eliminate 90% of the advertising from the sites I was visiting, my Web browsing sped up enormously.

Let me preface my solution by stating that it requires that you run your own local DNS servers, as I do on my home-office network.