Can you eraborate it more? In my experience, when Norton blocked entire site it immediately redirect the browser and no download of malicious file or any exploit could occur. Try Comodo Secure DNS. It seems we can use US version of NS2015, but Symantec already published regional restriction so it is possible someday my NS suddenly get banned. I'm still waiting official local version of NS is released, but why the heck they don't publish it yet for Asian-Pacific area?