ZyXEL Communications ZyWALL Series Support Note page 18

Step 5: Click on "ZyWALL" to connect to
the L2TP VPN. Fill in the L2TP password
and click "Connect".
Step 7. Go to Monitor > VPN Monitor > L2TP over IPSec to check the L2TP session.
Step 6: Device will show connected when
dial up successfully