A bit confused here...
Postfix has smtpd_client_restrictions & smtpd_recipient_restrictions.
smtpd_client_restrictions is 'Optional SMTP server access restrictions in the context of a client SMTP connection request'.
smtpd_recipient_restrictions is 'The access restrictions that the Postfix SMTP server applies in the context of the RCPT TO command'.
I was going to put some RBL-checks on incoming emails and Google sent me to http://www.us.sorbs.net/mailsystems/postfix2.shtml, where it suggest I should put them in smtpd_client_restrictions. However, I first decided to check up an old config where I had put such RBL checks in place earlier. And to my surprise I noticed that they are there in smtpd_recipient_restrictions!
Does it matter where they go? Or can they go in either?