Firstly, check out the options in
IE>Tools>Internet Options>Advanced>Search from the Address Bar.
Browsers work on IP addresses not words.
Then remember that your browser checks your host file before anything else to see if the words you put in are in the hosts file as an IP address.
If it's not in your hosts file your browser checks the big hosts file in cyberspace to get the IP address.
(I guess somewhere in here it checks your restricted & trusted sites too)
Upon finding the IP address your browser then uses it to send a request to the site & then it's out of your hands.
Making sense so far I hope.

Remembering that your browser checks your hosts file first you can by-pass everything else by putting entries directly into your hosts file that will point your browser to the correct IP address.
Hope this helps.