[postfix-es] En la lupa de un(os) Hacker(s)

[David González Romero]

Eso huele más a que tu server es Open Relay...

Un método bueno sería:

smtpd_helo_restrictions =
        permit_sasl_authenticated,
        permit_mynetworks,
        check_helo_access hash:/etc/postfix/helo_access,
#       reject_non_fqdn_helo_hostname,
#       reject_invalid_helo_hostname,
        permit

Donde /etc/postfix/helo_access
mail.tudominio.com.mx       REJECT
tu.num.ip.del.server          REJECT

smtpd_sender_restrictions =
        permit_sasl_authenticated,
        permit_mynetworks,
        reject_unauth_destination,
        reject_unknown_sender_domain,
        reject_non_fqdn_sender,
        #DNSBLs:
        reject_rbl_client dnsbl.sorbs.net,
        reject_rbl_client bl.spamcop.net,
        reject_rbl_client sbl.spamhaus.org,
        #reject_rbl_client combined.njabl.org,
        reject_rbl_client b.barracudacentral.org,
        hash:/etc/postfix/reject,
        permit

Donde: /etc/postfix/reject
tudominio.com.mx    REJECT

Con esto logras que NADIE tome tu Identidad para enviar a traves de ti mismo.

Saludos,
David