If your website does a lot of queries via domain names such as aggregating RSS feeds or even a Twitter app site that accesses Twitter API, you might benefit from installing DNS cache on your linux web server.
For most, you would benefit from installing DNS cache because it will save you a ton of time for your server to fetch IP addreses. (could be anywhere between 5 to 500ms).
I’ve actually found a great article showing you how to do this on a Linux desktop computer. It actually works fine on web servers too.
Check out WebUpd8.com for full instructions.
Some notes on CentOS users:
You can do “yum install bind-utils” to get the dig program.
