Changing what's on your screen won't help much when your boss has access to your internet logs, and potentially remote access to your computer... (Yes, these are both still things in startups today)
Recently they turned on blocks for a large number of sites like box, dropbox, google drive, slideshare, youtube, sourceforge, .... Someone might share company IP on the internet so lock it down. I think its just blind application of default rules but I've had no luck in getting even more reasonable stuff like sourceforge reversed yet. I'm worried it will be bitbucket and github next because they can be used to share files who needs that right?
I don't even understand why you'd go through all the effort. It's a silly position to put yourself in. If the IT policy bothers you that much, talk to somebody about changing it or find another job.
Routing all your traffic to a server in Online.net's network? At best I'm assuming you're pirating stuff.