Virtual Server not forwarding Source IP

You're not giving us much to work on. Can you please describe what situation you are trying to solve? If it doesn't work without Auto Map enabled, I'm guessing the F5 is not acting as the default gateway of your proxies, which is required in order to avoid SNAT. Please note that you can inject "X-Forwarded-For" for use tracking and later extract this from the request forwarded to your proxies (I know for certain you can do this with Squid, Cisco Ironport and Trend) More info about how to configure this on your VIP here: https://support.f5.com/kb/en-us/solutions/public/4000/800/sol4816.html