Please see this thread:
Click here for information on inserting headers in HTTP requests. If these requests are other than HTTP/HTTPS connections you will most likely require some redesign of the network.
Apparently you are SNAT'ing all incoming connections which may or may not be required depending on the network design. If BIG-IP is the default gateway for the servers then you should not need to do this, but if you do not SNAT and routing is not set up properly then your client connections will fail. (Network design discussion is not in the scope for this iRules forum...please see the BIG-IP LTM manuals on tech.f5.com (
Click here) for further info on SNAT)
Denny