With the help of some of the gurus here I've done lots of rewrites, but have never encountered this specific situation.
It starts with taking an old site and redirecting it's pages to pages on the new site without losing P.R. Easy enough, external rewrite, 301. But . . . . there is a legal requirement that there be an "interim" page with a "why you are here" message.
Referrer is not available in a rewrite as that is sent from a browser. I can't see any other way to "get" that the inbound request comes from the old server other than tagging it with a query string, which changes the nature of the link and is counter to the idea of the redirect (i.e., widget.html -> new-widget.html, not new-widget.html?somevars=somevals.)
We can't interfere with current site pages, and can't create duplicate placeholders to direct to. If I can detect the inbound comes from server A, I can read in/output pages with a message just for those visitors, leaving the pages intact.
I thought this should be simple, but I'm not seeing it. Any ideas?
