i tryed using the http_rffer to see where they were coming from but soon found out that that variable will be blank unless somoen has actually clicked on a link rather than being redirected.
Search is your friend “I was having a mildly paranoid day, mostly due to the fact that the mad priest lady from over the river had taken to nailing weasels to my front door again.”
If you were able to create a custom 404 error page, you could capture the url that they tried to access, and redirect it to the new domain with the same url. But that is depending if you can change your 404 error pages on your server on domain1.
Next thing you could do is, on your domain2, is check the referer field and capture the url they were trying to access. But again, you said referer field is blank.