no matter PP2P or L2TP.
here is the log:
I/SProxy_mtpd( 158): Stop VPN daemon: mtpd
D/VpnSettings( 2968): received connectivity: ikta3(pptp)★★★★: connected? CONNECTING err=0
D/dalvikvm( 2968): GC_FOR_ALLOC freed 3978K, 52% free 8580K/17799K, paused 52ms
I/dalvikvm-heap( 2968): Grow heap...