Is it possible to reject mail from sites with incorrect inverse DNS records

[Yusuf Goolamabbas]

Hi, I run a mail server with an upatched qmail-1.03 and tcpserver with rblsmtpd.

Is it possible to reject mail from sites which don't have correct inverse DNS 
records (PTR records). If there is patch for qmail/tcpserver, would appreciate a 
pointer to it and a usage example

Thanks, Yusuf
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