ExtraDNS saves time by intercepting DNS requests and storing replies in a fast, indexed database. The next time your system needs to resolve the same address, ExtraDNS instantly supplies the reply from its database. This decreases delays when loading a Web page (it also has to resolve addresses for the graphics, banners, and other elements of the page).
All IP numbers are not stored on every DNS server, and browsers usually search for them one by one to resolve the URL. ExtraDNS further speeds up the search process by searching many DNS servers simultaneously.