[ILUG-BOM] IPSec on kernels 2.5

Hi.

Does anybody have any experience on using VPNs on IPSec on GNU/Linux systems?

I know of freeswan, and tried my hand at it. But our setup has a masquerading firewall, which complicates matters apparently. The Windows users use SonicWall, and I have no idea how it handles things. So, no success with freeswan (help here will be appreciated too)

But recently, I switched to kernel 2.5.65+, which has support for ipsec builtin. Does anyone have any experience with 2.5 kernels and ipsec? A howto I found on the net wasn't much help. We have to authenticate with a login/pass to the remote site's VPN gateway, but I found description of no such thing in any of these howtos.

Thanks!