Before you buy this application, please test with the free "L2TP Connect(Demo)" which is also available in this market.
Auto Reconnect Mode:
Auto reconnect mode is added to "L2TP Connect" from version 2.0. In this mode, the app will attempt to reconnect if the VPN connection is disrupted. Some modified Android system will automatically kill any background service after your screen is turned off. To avoid "L2TP Connect" being killed, you need add it to your system's whitelists.
To Samsung 6.x users:
On Samsung 6.x VPN is reported not to work unless the VPN app is exempted from Powersave features. You should disable it by yourself.
Settings -> Battery -> App power saving -> Detail -> L2TP Connect -> select "Turned Off"
Settings -> Battery -> Power Saving Mode -> "Restrict all background data": Off