From Amahi Wiki
There are two supported options for VPN in Amahi:
- An IPsec VPN which is built in on iOS devices like the iPad, iPhone, iPod (without need of jailbreaking/rooting). Details at IPSec VPN
- An OpenVPN solution, also as an app. This is a popular open source VPN stack. This is not included by default in iOS or Mac OS X.
Both of them require forwarding ports to work from outside your network to your HDA.
We offer a free OpenVPN tester in your console in Amahi.org to test your setup, as a convenience, because the VPN cannot be tested inside your network.
To get started, pick one and install the app and the relevant client software in your client computer or mobile device, then configure it for remote access.