The ISC shares an interesting account of how Chrome may prefetch DSN info when web addresses are entered into the browser. This option can be turned off if desired, but may slow browser performance a little.
Google Chrome – Prefetching DNS requests
QUOTE: Thomas, wrote about weird DNS requests that he is seeing coming from his machine. After spending some time he found out that Chrome is sending those requests that he could not explain every time it is started. Since I spent some time on this (long) time ago, I decided to pay more attention to Chrome’s DNS request.
So, in order to speed up browsing Google Chrome does a lot of DNS requests in advance (DNS prefetching – this can be even turned on and off in Chrome’s options). When Chrome is started it will lookup domain names for previously opened web pages early in the startup process so if the user clicks on one of those links Chrome can connect to the target site immediately.
How bad is this? Well, it’s not too bad but it is certainly causing some extra traffic, especially since it depends on caching of (mostly) negative answers. Now, good thing for those wanting a bit more privacy is that you can turn of DNS prefetching in Chrome’s Options menu so it won’t try to resolve domain names as you type
MORE INFORMATION – Chrome – Prefetching DNS requests