I'm quite confused with Virtual Tunnel Interface (VTI) routing. I've set up VPN concentrator on Cisco 870 with VTI -- this interface is used as nat inside and it works almost fine -- TCP traffic is correctly translated, OK. But problem is with UDP traffic and maybe due the same reason doesn't work echo request from the router to VPN client.
I tried to debug packet flow:
IP: tableid=0, s=220.127.116.11 (FastEthernet4), d=10.10.70.9 (Virtual-Access2), routed via FIB
IP: s=18.104.22.168 (FastEthernet4), s=10.10.70.9 (Virtual-Access2), g=10.10.70.9, len 225, forward
(it's reply from DNS server)
and I seems to me correct, packet is correctly translated and routed to Virtual Tunnel Interface, which should pass it to tunnel encapsulation and delivery it to the VPN client, but it ends somewhere between -- VPN client doesn't get packet, which isn't even counted in Virtual-Access interface statistics.