yeah, it probably isn't port 80, but certainly something else. If you can get there with http, then that protocol is certainly not blocked.

I have both a VPN at home, which I can access, and then the traffic gets routed there, so I know I can always access anything.

Or, you can setup a vpn connection to work, or to home, or sometimes I'll setup a GOTOMYPC or mywebexpc connection, to home. this is a cheap way to do a VPN without DOING VPN.

Sometimes, a proxy server access will get around these things, or a wifi connection server, like the google secure access, which I still sometimes use which routes all traffic THERE, and then securly to the laptop. That works sometimes.