I am looking for a solution as to what would be the VPN software for multiple OSes and Devices. I currently have 15 systems to connect to a VPN. I was using Hamachi from LogMeIn but their lack of Android support really upsets me, and their limited support for Linux OSes is also a let down.

90% of my systems are Ubuntu 11+ systems, only 2 are Windows XP. But I also have a few people, maybe 3 that need to connect to it from Android devices. This is where Hamachi has let me down and I want to move to my own VPN solution.

The server would be a simple VPS running CentOS. So I need some VPN software that allows connection of those to a Linux based server.

I wanted to go with OpenVPN, but I am under the opinion that in any OS you have to have their software to connect to the VPN. Ubuntu supports VPN's out of the gate, but OpenVPN requires extra software to be installed, I don't want this if I can help it. Same with Windows and same with Android.

Plus android mostly requires rooted devices for OpenVPN, at least from what I've read.

I was looking at maybe L2TP, but I'm not sure how easy it is to get Ubu systems connected with it as I haven't found much on the subject, let alone Window's XP machines.

I know Android connects out of the gate to it. I don't know much about L2TP but I know it's a pain to get running in CentOS from what I have read.

Now the last option is some sort of software for PPTP but I've never read anything on it and don't know if all systems are compatible with it.

What would be your solution to these devices and multiple OSes? OpenVPN seems to be my heading I just don't like it that it always requires software to run and rooted Android Devices.

Any solutions for this and install solutions? Maybe a different OS for the server like Ubuntu would make another type of VPN easier?