Win 8 does not support hosts file blocking website function

        The Windows hosts file provides an easy way to redirect or block certain URLs, such as assigning URLs hijacked by DNS to the correct IP. In theory, you can add any domain name, host, or website to the hosts file to block them, but in Windows 8, this method works for some websites.

According to foreign media Ghacks, in Windows 8 RTM, there are two websites that you can't use the hosts file to block (it's not clear whether there are other websites as well), namely facebook and ad. Doubleclick, the most popular social networking site and the most popular ad serving domain.

You can still add any domain name to the hosts file and direct it to an IP, but you will find that the domain name of facebook and ad.doubleclick will be reset after opening the browser. Although you re-open the hosts file after modifying it, you will see that these changes are still there, but once you open your browser, the hosts file will automatically delete them.

Some people find that this is related to the design of Windows Defender to protect certain domain names. If you turn off Windows Defender, the above problem can be solved. (Note: Windows Defender in Windows 8 integrates the previous Windows Defender feature and anti-virus software MSE)