Linux is one of the best choice for using VPN service both server and client.
here is the collection some links and information I used for VPN.
https://openvpn.net/index.php/access-server/docs/admin-guides/182-how-to-connect-to-access-server-with-linux-clients.html
Installing an OpenVPN client:
Usually, the easiest way to install an OpenVPN client is to use the package management system for your particular Linux distribution. Run one of the following commands (as root):Fedora/CentOS/RedHat:
yum install openvpn
*NOTE: OpenVPN Access Server is not compatible with any version below the 2.1 OpenVPN Community/Linux client!
Ubuntu/Debian:
apt-get install openvpn
Once the openvpn package is fetched from the Internet and installed, run the client with the --version argument to make sure that it is version 2.1:
openvpn --version
OpenVPN 2.1_rc15e x86_64-unknown-linux-gnu [...]
[...]
[...]
Running the OpenVPN client with the downloaded client config file:
Usually, the easiest way to install an OpenVPN client is to use the --config argument to specify the location of the downloaded client config file:openvpn --config client.ovpn
Caveats:
When a Linux/Unix client is used with Access Server, the Access Server is unable to alter the DNS settings on the client in question.WIndows OS can use L2TP vpn service as default.
http://freel2tpvpn.com/
Free L2TP VPN Account
VPN Type: L2TP VPNUS VPN Server: us.freel2tpvpn.com
65.60.11.21
UK VPN Server: uk.freel2tpvpn.com
77.92.87.171
VPN Username: vpn
VPN Password: freel2tp
VPN Secret : freel2tp
Here is the list of free VPN services available.
http://www.vpngate.net/en/
http://www.vpngate.net/en/howto_l2tp.aspx
http://www.vpnbook.com/