Probably a basic question.

[Toby]

Just a guess, but a null value for http_referrer would be a type-in or bookmark and no http_referrer parameter at all would be blocked referrer.

It has to be in the HTTP header, that's the only source of referrer data for incoming traffic.

[ecchi]

Originally Posted by Toby

Just a guess......It has to be in the HTTP header, that's the only source of referrer data for incoming traffic.

Thanks. Before I posted this thread I did a Google search for "no referrer" and got nothing useful (which was why I posted). This weekend I'll try searching for tutorials on "HTTP header" and see if I get anywhere. I've got a pile of urgent "non adult" web work to do today and possibly tomorrow, but I should be able to get back to the script Saturday or Sunday.