First Method :
You can install a 'phproxy' add-one in Mozilla. When you want to access any blocked site there will a 'ph' symbol in Mozilla to click on that symbol you will redirect that blocked site easily. You can install phproxy add-one from here Download .
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There are many numbers of proxy sites. First open that proxy site and copy your download url to that proxy sites option.It will open your site easily.These are some proxy sites.