We have setup a GRE/IPsec Tunnel between two of our sites. Everything is working great, except for one issue. Our web gateway/proxy uses the originating IP address to authenticate the user. Due to the NATing it does not pickup the originating IP address but rather the IP address of the Mikrotik on the side of the web gateway. For the users/computers on the local network it is obviously working fine, but for all the users on the other side of the tunnel it is not. Is there anyway to configure the tunnel such that the addresses are not translated?

Any assistance would be much appreciated.