One of these days I would like to setup and mess around with an opensource IPSEC server and connect our iOS devices to it. One thing our F5 can do is NT authentication and then pass those credentials on to our Qlikview Server, I wonder if StrongSwan can do that?
For a Cisco IPSec Gateway on Linux, I recommend you use Open source package StrongSwan for your iOS VPN on Demand
Use –enable-cisco-quirks parameter to build StrongSwan to make it compatible with Cisco IPSEC. It is a stable certification based, IPsec Gateway on linux that is compatible with iOS VPN on Demand requirements.
Check following link for setup iOS on StrongSwan:
Authentication uses XAUTH and certificates (authby=xauthrsasig).The described setup has been tested and confirmed working on an iPad 2 with iOS 4.3.1, but is expected to work on all other iOS devices (iPhone, iPad, iPod Touch) running an up to date iOS version.