How to bypass proxy from intranet

I work in company branch and my company don't have inteet acces, They just use intranet. lately we know than we can surf with proxy setting in our browser, use main company IP and user password too. but the problem is there are many site is blocked by this proxy even the normal site. I try to use ssh but i can't coect. my office use 10.16.7.254 DNS and main company use 10.254.130.49 port 808. anyone can help me to bypass this via ssh or anything?