SAIF L2TP VPN - Android
1. Start the "Settings" application on Android.
2. Tap "VPN". Click the "Add VPN profile" button to create a new VPN connection setting.
3. A new VPN connection setting editing screen will appear.
 ● Input something string on the "Name" field (e.g. "SAIF L2TP VPN" ).
 ● Choose "L2TP/IPSec PSK" in the "Type" field.
 ● Set the Server as "l2tpvpn.saif.sjtu.edu.cn".
 ● You also have to enter your SAIF user name and password in the field user-name, password.
 ● Enter the secret (pre-shared key) "090419".