I'm looking for a solution similar to the one in this question, except that I don't have a linux computer. I have windows computers that could be set up to accept VPN connections. Preferably I want to set this up on either Windows Server 2003 or Windows XP.

I'd like to connect different devices (e.g. iPhone, iPad, laptops, etc.) that are on open unsecure wireless networks (e.g. the one's you see at places like Starbucks) to this VPN to ensure that all my data is secure.

I found an article that shows that you can enable VPN connections on Windows XP. After following those steps, though, I'm not sure what to do. Which ports do I open on my firewall? Which VPN settings do I use on my devices such as the iPhone? Do I use L2TP, PPTP, or IPSec? What's the difference between these? Are there any other steps missing in that tutorial?

I'm hoping that since Windows has this built in feature, that it will be much simpler to set up rather than having to deal with setting up something such as OpenVPN.

If I follow those settings and enable port forwarding on port 1723, and then use the following settings on the iPhone:

• PPTP
• (IP Address)
• RSA SecurID: Off
• Encryption Level: Auto
• Send All Traffic: On
• Proxy: Off

It shows "Connecting..." then "Disconnecting..." and the following error message:

VPN Configuration
A connection could not be established to the PPP server. Try reconnecting. If the problem continues, verify your settings and contact your Administrator.

I'm using a user account that I enabled privileges to in the VPN settings on the Windows machine.