TheOS.IN Stories, advice, and random thoughts from a thirty-something guy. The most basic task of DNS is to translate hostnames such as theos.in to IP address such as 74.86.49.131. In very simple terms, it can be compared to a phone book. DNS also has other important use such as email routing. This is my list of better, fast public dns servers and free dns server (as compare to your ISP / DSL / AD