I’ve seen longers lits of IP addresseses but this seems to do the trick for me
127.0.0.1 www.facebook.com #127.0.0.1 facebook.com #127.0.0.1 static.ak.fbcdn.net #127.0.0.1 www.static.ak.fbcdn.net #127.0.0.1 login.facebook.com #127.0.0.1 www.login.facebook.com #127.0.0.1 fbcdn.net #127.0.0.1 www.fbcdn.net #127.0.0.1 fbcdn.com #127.0.0.1 www.fbcdn.com #127.0.0.1 static.ak.connect.facebook.com #127.0.0.1 www.static.ak.connect.facebook.com