I am new to the whole 'private VPN server at home thing', but I've set up my pi to host a PPTP VPN server. I’m just testing it out and plan to switch to a more secure method, like openVPN, in the future.

The server is working pretty well so far; I've been able to connect to the internet through the server with both my nexus 7 and iPhone while out of the house. However the issue comes up when connecting my devices through the WiFi at work (I'm not sure what VPN protocols or security features they have implemented in the background and have no clue where to start to figure this out). Connecting my tablet's internet to my home IP while at work was half the reason to create the VPN in the first place. I'm assuming that the IT Department has this type of connection blocked. I should note that I'm able to connect to my sftp server from work but not my friends ftp server.

Since the SSH connection works, are there VPN types with run over these protocols? It would still have to work on various operating systems, i.e. Mac OS, iOS and Android KitKat. Any thoughts or ideas to test would be most appreciated.