Forward proxy with an internal and external proxy irule config

Hi All,

I had a question, we are currently using ZScaler via a GRE Tunnel from the F5 which works great and has replaced our EOL Blue-coat appliances, however we have an issue when we point to the proxy we can not resolve internal resources. Where as our Blue-coats we were able to point to it and it could do internal and external.

To work around this I have created an Internal Proxy using the F5 Irule (devcentral.f5.com/s/articles/http-forward-proxy-v32) However I am struggling to put in some smarts to say if you want to go to an internal IP Address (10.0.0.0/8) go to the Internal Proxy VIP else go to the ZScaler VIP.

Any one has a method to create an iRUle which is able to define which VIP/Pool to use based on the desination IP address you wish to go to.

Any guidenace would be appreciated.

Thanks

Monty