I’m not sure if this will be attached to the thread to which I’m responding, so the original question is below.
I use an entry in main.cf of “smtpd_sender_restrictions = check_sender_access hash:/Library/Server/Mail/Config/postfix/sender_access permit ”; The file “sender_access” appears: . mydomain1.org.uk REJECT .mydomain1.org.uk REJECT mydomain2.org.uk REJECT .mydomain2.org.uk REJECT . . . To prevent my own senders being blocked, all outgoing mail is sent via Submission (port 587), with no internal smtpd_sender_restrictions in master.cf (but external access must be sasl authenticated on Submission). I hope that helps Janette Cobb From: owner-postfix-us...@postfix.org [mailto:owner-postfix-us...@postfix.org] On Behalf Of John Baker Sent: Wednesday, March 30, 2016 10:46 AM To: postfix-users Subject: best practice for blocking fake local domain senders We've gone a long time without specifically needing this but suddenly we are getting bombarded with spam \ pretending to be from one of our addresses but originating from outside. So I need to block mail with a \ @marlboro.edu<http://marlboro.edu <http://marlboro.edu/>> sender unless it helos from local servers or specific external IP \ ranges. I have a few ideas on how to do this but but wondered if anybody could quickly point me in the direction \ of best practices for this. Is there a simple way or is it best to use smtpd_restriction_classes? thanks -- John Baker Network Administrator Marlboro College Phone: 451-7551 Cell: 490-0066 -o-o-o-o- KUGRO Disclaimer: This message (including attachments) has been scanned for both viruses and spam. The message has, in addition, been electronically signed (DKIM) to prove its origin and authenticity. Every effort, therefore, has been taken to ensure the integrity of this message, but that does not absolve the recipient of the responsibility to take appropriate anti-virus action nor does it imply any warranty or guarantee whatsoever!
