pass client_ip to server (not http or https)

You can manipulate the packet headers and data with a rule, but the protocol it's being sent over needs to support the data you're changing/adding. HTTP supports custom headers, so you can insert the original client IP address and then configure the web server to log that custom header. Do you know if the protocol you're using supports something like this?

 

 

If the protocol doesn't support it, you could consider changing the default gateway on the server to the BIG-IP. You could then disable SNAT on the virtual server so the original client IP address is preserved.

 

 

Aaron