question about network shield

Avast Free Antivirus / Premium Security
1

How does network shield block dangerous websites? by blacklists or other technology?
Can you explain me how it work if it does not have blacklists?

Thanks

2

Please see the link below at the avast web site and scroll down until you come to the Network shield.

http://www.avast.com/en-eu/free-antivirus-download#tab2

You can also read about the other components of avast at that link.