Here is the scenario: US ASA 5510/switch 3560, Singapore ASA 5515/switch 3570US site 10.254.0.0/16 mpls router 10.254.18.14 vlan18 server 172.31.52.110Singapore site 10.253.0.0/16 workstation 10.253.28.0/24 valn28Site to site tun...
So you were correct i had to add a the 172.31.0.0 network to both sides of the tunnel, and a NAT and we were able to get the traffic from singapore through the tunnel successfully. thanks.