I use Private Tunnel VPN. The support website (under Connection questions: How do I connect to PrivateTunnel using Ubuntu Linux?) recommends this for Ubuntu :
Configuring Network Manager to Validate Server Certificates
Since the default configuration cannot validate server certificates properly, it is possible for someone to impersonate as PrivateTunnel and compromise your data integrity. For this reason, it is strongly recommended that you apply the patch below so that server certificates are validated prior to a successful connection. To do this, copy and paste the command below into a Terminal window (this patch will have to be reapplied if you upgrade your operating system or if the plugin is upgraded to a new version):
mv /usr/sbin/openvpn /usr/local/sbin; echo -e '#!/bin/bash\n/usr/local/sbin/openvpn $* --ns-cert-type server &\ntrap "kill $!" EXIT\nwait $!\n' > /usr/sbin/openvpn; chmod +x /usr/sbin/openvpn
Will i need to do this in elementary OS Freya?