My understanding of client and sender are these: Client: An application used to send, receive e-mail messages. Sender: The from or sender "name" in the header that shows who (is claimed to have) sent the email.
The context of the use that has me concerned are these: smtpd_client_restrictions and smtpd_sender_restrictions I currently have these lines in main.cf: check_client_access=hash:/etc/postfix/access smtpd_client_restrictions = permit_mynetworks hash:/etc/postfix/whitelist reject_rbl_client zen.spamhaus.org reject_rbl_client bl.spamcop.net reject_rbl_client dnsbl.njabl.org reject_rbl_client blackholes.five-ten-sg.com=127.0.0.4 reject_rbl_client blackholes.five-ten-sg.com=127.0.0.5 reject_rbl_client blackholes.five-ten-sg.com=127.0.0.6 reject_rbl_client blackholes.five-ten-sg.com=127.0.0.7 reject_rbl_client blackholes.five-ten-sg.com=127.0.0.8 reject_rbl_client blackholes.five-ten-sg.com=127.0.0.9 reject_rbl_client blackholes.five-ten-sg.com=127.0.0.10 reject_rbl_client blackholes.five-ten-sg.com=127.0.0.11 reject_rbl_client blackholes.five-ten-sg.com=127.0.0.13 permit smtpd_sender_restrictions = check_sender_access hash:/etc/postfix/greylist check_sender_access hash:/etc/postfix/sender_access permit_mynetworks reject_unknown_sender_domain To me the content of the sender_access hash makes sense if it contains terms such as luck...@yaha.com DISCARD Does it also work correctly if that same files also has terms such as 64.94.244 DISCARD where the intent is to block any of 64.94.244.xxx ? Right now that ip address example shown above (64.94.244) is in the sender_access file (and the sender_access.db) but the log file shows events such as this: Sep 27 17:56:19 mgxx postfix/cleanup[22432]: 596A81FFCD: hold: header Received: from av7.experience.com (unknown [64.94.244.50])??by mgxx.cnm.edu (Postfix) with SMTP id 596A81FFCD??for <gle...@cnm.edu>; Sun, 27 Sep 2009 17:56:16 -0600 (MDT) from unknown[64.94.244.50]; from=<no_re...@experience.com> to=<xx...@cnm.edu> proto=SMTP helo=<av7.experience.com> Sep 27 17:56:19 mgxx postfix/cleanup[22432]: 596A81FFCD: message- id=<27390832.651.1254095751632.javamail.r...@av7.experience.com> Sep 27 17:56:19 mgxx postfix/cleanup[22432]: 596A81FFCD: warning: header Subject: eRecruiting Saved Search - Abq-Lots from unknown[64.94.244.50]; from=<no_re...@experience.com> to=<xx...@cnm.edu> proto=SMTP helo=<av7.experience.com> Sep 27 7:56:22 mgxx MailScanner[9931]: Requeue: 596A81FFCD.2D1A1 to C98C42016A Sep 27 17:56:22 mgxx postfix/qmgr[24665]: C98C42016A: from=<no_re...@experience.com>, size=33955, nrcpt=1 (queue active) Sep 27 17:56:22 mgxx postfix/smtp[23167]: C98C42016A: to=<gle...@tvimail.cnm.edu>, orig_to=<gle...@cnm.edu>, relay=tvimail.cnm.edu[198.133.181.119]:25, delay=5.7, delays=5.6/0/0/0.03, dsn=2.5.0, status=sent (250 2.5.0 Ok.) Sep 27 17:56:22 mg05 postfix/qmgr[24665]: C98C42016A: removed Based upon my understanding of the definitions of the terms I have always been uncertain about putting ip blocks in the same file. I have been told it has been working practice at this college for years before I got here. I need to be certain we are doing the right things. -- Robert Lopez Unix Systems Administrator Central New Mexico Community College (CNM) 525 Buena Vista SE Albuquerque, New Mexico 87106