I've got a L2TP/IPSec VPN set up on CentOS (Amazon AMI) with racoon, ipsec-tools and xl2tp.
I'm using a version of racoon from this repo, as it allows the use of IPSec ID wildcards (or no specification thereof), following this tutorial.
I'm able to connect to my VPN from both an Android (ICS) and an iPad (iOS 5), however, I'm unable to connect from a Windows machine (have tried several) due to a 691 error.
So, what can I do?