forward proxy to allow HTTP CONNECT

I am curious how to implement explict profile in ltm && apm. Now I try to set one vip in ltm as a http/https proxy.

Robert, I see that you've posted a few questions recently, one about 2-factor auth, another about using a portal, and now this. Are these all related? Can you elaborate on what you're trying to do?

APM portal mode is a reverse proxy function that encapsulates internal applications inside a single external namespace. When you mention "explicit" I have to assume you're referring to a forward proxy use case, where you want to control outbound access to the Internet. Technically speaking, the basic forward proxy functions are built into LTM in 11.4 and above. You have a few options, including explicit mode, where the client must enter a proxy address into their browser, transparent mode, where the BIG-IP becomes the client's default outbound route, and variations of each of these. In either case, HTTP and HTTPS can be handled seamlessly. If you want advanced control over outbound access, then the Secure Web Gateway, a separately licensed function of APM can provide secure screening of that traffic. You don't need an iRule anymore to do forward proxy.