DNS Prefetching Firefox addon speeds up your browsing experience by resolving and caching DNS lookups before you actually click on a link. Without this technique, the DNS lookup is performed only when you click on the link, adding a wait of 250ms (on average) before the page even starts to show up.DNS Prefetch does not try to resolve relative links, or resolve links whose host is the same as the current page's host, since the current site's DNS record is almost certainly already cached. DNS lookups are performed asynchronously, after the page has loaded, so that your browsing experience is never delayed or interrupted.
Your privacy is safe. While DNS Prefetch does perform a DNS lookup for each different site that exists in a link on your current page, it does not connect to those sites or download any data from them. Unlike page prefetching, the only servers contacted are your computer's DNS servers.
DNS Prefetching is already available in Google Chrome, and is planned to be inbuilt in Firefox 3.5.
[via instanfundas]
