L2TP/IPSec NAT issue

Question

I am a little confusing.

A(L2TP/IPSec VPN server ) ---- B(router) ------ (internet) ------- C(router) ------ D(client)

Can a L2TP/IPSec VPN server(A) behind NAT,serve clients(D) behind other different NATS? Can the IKE message corrected be routed to the L2TP/IPSec VPN server behind NAT?

PS: I dont have any authority to change the B router's NAT configuration. A & D can communicate with the same server who has a public IP address.

Answer 1

I got the answer myself IKEv2 mediation has a solution for this kind of problem http://www.strongswan.org/docs/LinuxTag2008-strongSwan.pdf