Redirect external traffic to internal sharepoint page

SharePoint has this thing called "Alternate Access Mappings" (AAM) that is basically SP's way of mapping different applications to different URLs. The most frustrating thing about it is a requirement to exactly match the host name(s) specified in AAM, even if you only have ONE application. So if you have "http://sharepoint" defined in AAM, and you don't access it with this URL, then it'll just redirect you to it. This of course presents a problem if http://sharepoint doesn't resolve to any real IP address outside of your local environment. So there are generally two ways to address this behavior:

1. Configure AAM with the external URL names that users will type in the browser, and that are DNS resolvable, or

2. Configure an iRule to inject an HTTP Host header that makes SharePoint think you're asking for it by a specific name (what you have configured in AAM). That might look something like this:

   when HTTP_REQUEST {
       HTTP::header replace Host "sharepoint"
   }