As a network engineer at my company, I administer our Fortinet products which includes Fortiguard Web Filtering. May I ask why you are trying to bypass the web filter? Have you checked with your admin to allow/provide you with the access you need?
I realize sometimes we want to browse the Internet at work, but we have to remember we are at work to work. Many times we can get carried away browsing the Internet, along with consuming network bandwidth that is not related to work.
I have many users trying to bypass the filter at work, and so far have had no luck. Please keep the above advice in mind. One day you might be that network administrator battling users trying to bypass security filters, and let me tell you ...it is irritating.