Hi, first apologize me for the grammar, english isn't my native language. The problem I have is users from our local zimbra mail are getting spam messages from other email addresses who don't exist, like annymous172167@ourdomain I found that the problem can be OpenRelay in postfix configuration. I did this test tech-recipes /send_mail_via_telnet_test_for_open_relay/ (link edited because I cant post links) and foud that I can send emails via telnet without any authentication. To resolve the problem, I tried to change the postfix configuration. My original conf file (/opt/zimbra/postfix-2.10.3.2z/conf/main.cf) was "smtpd_sender_restrictions = check_sender_access regexp:/opt/zimbra/postfix/conf/tag_as_originating.re, permit_mynetworks, permit_sasl_authenticated, permit_tls_clientcerts, check_sender_access regexp:/opt/zimbra/postfix/conf/tag_as_foreign.re, check_sender_access hash:/opt/zimbra/postfix/conf/access_table" And I tried to change to "smtpd_sender_restrictions = reject_unknown_sender_domain" But when I run "$postfix reload" the configuration come back to the original one, without any changes. (I found that configuration change on this forum "How to disable open relay on Postfix?") I appreciate any help. Thank you
I found the solution, thank you all! jorgedelacruz(.)es/2014/04/03/zimbra-seguridad-i-parte/ (in spanish)
