Rewrite rule forward to specific domain and port

It doesn't matter what port the server is listening on, LTM is acting as a proxy so your Virtual Server can be on port 443 and your pool member listening on 7012 and it all just works; the client connection is terminated on 443 and a new connection is created from the F5 to the pool member on 7012. No need to use an iRule to change the port, it's automatic. You could have six pool members all listening on different Service Ports and it wouldn't matter, it would work.