Is transparent NAT possible? The applications need to be aware of the source IP address to process. The only way I can see to do this is insert the source into the header. I seem to recall reading about transparent NAT, and no NAT, but I cannot find it now.
All ideas welcome.
BTW, I want to clarify that client nat is not on by default. You must have configure it and if you do so, you lose information about the client ip. The solution to insert the info into the http header is a good one.