I follow IPSec instructions to configure the Router successfully:
And configured the PAT successfully:
But If I combine two demos together. The host behind the NAT cannot ping the remote host.
It will show U symbol ( I guess this means is unreachable ) unless I erase the NAT command ( no ip nat inside source list 1 interface gi0/0 overload ).
Is there any extra command I have to configure? If so, can you please explain why?
It really depends on your topology and on the location at which you have applied NAT. Are you attempting to have the tunnel traverse NAT (in which case you will need to use NAT Traversal) or are you applying NAT at one of the two sites being connected over the VPN? Can you give us some more information about your setup so we can help you further? You might find some of the following links useful as well: