On 22.09.2017 18:19, Davide Marchi wrote: > Is there any way to tell to reject any mail coming to the MX backup > server, if the primary server is up?
Have you not just recently asked this on the Postfix mailing list? Somebody did. It is not a SpamAssassin issue, since SA only gets involved after Postfix has already accepted the mail. The only way to make a backup MX "spam safe" is to use the same tests/policies on both primary and secondary MX. > on my server I guest i...@foo.org, and its alias: ali...@foo.org and > ali...@foo.org, and stop. The spam come from ali...@foo.org, that > doesn't exist, how I could reject and prevent to delivery from these > address, without compromise the backup server? Add a Postfix sender restriction that rejects all mail apparently sent by foo@your.domain via port 25 of your MX. Only allow this to happen on port 587 (submission) and for authenticated users. See Postfix docs for details. -Ralph