I'm attempting to set up my Windows 8 PC as a VPN server and connect to it with my iPad. I've followed the instructions described here. After I enter in my VPN information on my iPad and attempt to connect, I briefly see
1 client connected under the
Incoming connections icon in
Control Panel/Network Connections. This quickly goes away (back to its default
No clients connected message) and after several seconds, I get the following message on my iPad:
A connection could not be established to the PPP server. Try reconnecting. If the problem continues, verify your settings and contact your Administrator.
I should note that my iPad is not connected to my home Wi-Fi network. To test the connection, I'm tethering my iPad through my Android phone's portable Wi-Fi hotspot.
I'm not sure where to go from here. Using Wireshark, I can see that packets are being exchanged on port 1723, so I'm assuming it's not a firewall issue. I've tried different permutations of the username, (e.g. MYCOMPUTERNAME\VPNUser, MYCOMPUTERNAME/VPNUser, VPNUser) without any luck.
Any ideas of what might be preventing my iPad from connecting to my Windows PC via VPN?
Edit: Upon further research, it looks like the GRE Protocol 47 might be the culprit... is there a concrete way of testing whether my router supports the forwarding of this protocol?