reply to oh6hfx
Re: when USG20 L2TP/IPSEC connected, cant ping USG20 wan anymore
After reading your answer I wrote again the situation with better
details. Then I realized that all my devices here are behind same ADSL NAT.
Tried to turn of Wi-Fi in my smartphone and logged in VPN with 3G connection. Seems to be working ok now! I can still ping USG WAN with my desktop pc and access admin www...
Only negative thing seems to be that also this USG leaves IPSEC SAs hanging dead...