Filtering out accesses from dip.t-dialin.net

[Peter_LT]

Hello Folks,

I'm wondering if any of you have recently had problems with stupid recursive
calls that throw a 404 error not found and the remote host is *wotever*dip.t-dialin.net?
A couple of days ago, over 43,000 calls in a relatively short while were made,
similar to this one...

pd9eaceb6.dip.t-dialin.net - - [20/Apr/2008:02:35:55 +0100] "GET /car2blog/css/w3c/css/css/css/css/w3c/css/w3c/w3c/w3c/w3c/css/css/css/css/w3c/w3c/w3c/w3c/css/css/css/w3c/css/css/css/css/w3c/w3c/css/css/w3c/css/css/w3c/css/css/css/css/css/w3c/w3c/css/css/w3c/css/w3c/css/css/w3c/w3c/w3c/w3c/w3c/css/w3c/css/w3c/w3c/css/css/w3c/w3c/css/w3c/css/css/css/css/w3c/css/w3c/w3c/w3c/css/w3c/css/css/css/w3c/css/css/css/w3c/css/w3c/css/w3c/css/css/css/css/w3c/css/css/css/w3c/w3c/css/w3c/css/w3c/w3c/w3c/css/css/w3c/w3c/w3c/w3c/css/css/w3c/w3c/css/css/home.php HTTP/1.1" 404 3211 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET)"

I've had several bad problems before from dip.t-dialin.net users so I'd really
like to be able to ban any further stupidity. Of course I could try placing a
deny from into the .htaccess file, but the upshot of that is everyone suffers
because of DNS look-up intervals, and why should they?

I employ the Kloth.net web robot trap, so I'm looking at placing another on
just a few selected pages that will re-direct dip.t users toward that trap,
obviating the need to have the .htaccess overhead. I'm guessing that I
could do this in PHP using gethostbyaddr(), but I'm not sure how to implement it.
Most of stuff on the PHP site on this subject is way over my head! Any help
much appreciated - thanks