iOS supports 3 VPN solutions: L2TP, PPTP and IPSec and currently I'm using PPTP connecting to a Ubuntu server.
Also, there are several problems: PPTP configuration has to be tunned on both ends in order to make it work and also I heard that PPTP can be broken in just 4 hours.
Is any other better solution for setting up Apple compatible VPNs that would not require buying some commercial software.
Best Answer
Why not set up L2TP if you don't want to harden PPTP further? There are a plethora of guides on the internet on setting up VPN using AWS free service micro tier instances and Ubuntu.
Here is one article from the AWS support forum with a discussion and links to how-to articles for setting up L2TP over IPSec on Ubuntu:
https://forums.aws.amazon.com/thread.jspa?messageID=286936