Blocking spams for hosted zimbra



  • hello

    ZIMBRA email server is hosted and spams just keep coming.

    How can we block spams. Could we use pfblockerng? or what is best for this?

    Many thanks


  • Moderator

    Zimbra uses Postfix, so your first step is to use DNSRBLs. Your biggest bang would be to add Spamhaus Zen.

    You can run the following command to see what restrictions have been configured:

    zmprov gacf | grep zimbraMtaRestriction
    

    Recommend the following settings:

    zimbraMtaRestriction: reject_invalid_hostname
    zimbraMtaRestriction: reject_non_fqdn_hostname
    zimbraMtaRestriction: reject_non_fqdn_sender
    zimbraMtaRestriction: reject_unknown_client
    zimbraMtaRestriction: reject_unknown_hostname
    zimbraMtaRestriction: reject_unknown_sender_domain
    zimbraMtaRestriction: reject_rbl_client zen.spamhaus.org
    zimbraMtaRestriction: reject_rbl_client bl.spamcop.net
    zimbraMtaRestriction: reject_rbl_client b.barracudacentral.org
    zimbraMtaRestriction: reject_rhsbl_client dbl.spamhaus.org
    zimbraMtaRestriction: reject_rhsbl_reverse_client dbl.spamhaus.org
    zimbraMtaRestriction: reject_rhsbl_sender dbl.spamhaus.org
    

    For pfBlockerNG, I wrote a script to import over 50 Blocklists here:
    https://forum.pfsense.org/index.php?topic=86212.msg549973#msg549973

    It has a MAIL section which will also help reduce SPAM.


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