PPTP was probably blocked because it needs the GRE port. And I think xfinitywifi only allows UDP/TCP.<p>I use OpenVPN over TCP and UDP on xfinitywifi all the time. In fact, I have a wallwart router configured for it. Plug it in, ssh in, set the wifi, and I have a relatively secure SSID I can use.<p>One day the UDP VPN stopped working. I found out it was because the MTU on xfinitywifi changed to ~1300. Sending a packet with a larger size would result in dropped packets which would cause some stuff to work, but not all. Setting the mssfix parameter to something lower in OpenVPN fixed it.<p>You can test this by varying the payload size in ping.<p>TCP worked fine the whole time.