Ministério da Ciência e Tecnologia


Message Envelop Check

 Verb HELO:

  • The hostname provided by system client MUST BE full name (host+domain) - FQDN (Full Qualified Domain Name). NetBIOS (Microsoft Network) is not allowed here.
  • The hostname provied MUST maches to reverse DNS query (what name has the IP address?) and that name MUST match with the IP Address (Direct DNS Query). Misconfigured system is not allowed here.
  • Under failure the message will be REJECTED, and the IP address will not be black-listed.


  • The domain name part of email address must have a MX ou NS record pointing to domain part of HELO client name.
  • Fake names provided by HELO will REJECT the message, and the IP address WILL BE inserted in black-list..
  • Under MAIL FROM domain failure will SUSPEND the message delivery, without black-list registration.
  • Combined failure condition implies in MESSAGE DISCARD and BLACK-LIST REGISTRATION.

 Verb RCPT-TO:

  • MAIL-RELAY tests or proposital delivery will DISCARD the message with black-list regsitration.
OBS: When you contract a ISP for hosting your mailboxes andfor your domain then the ISP MUST CONFIGURE their and YOUR system properly. Misconfigured systems and spammer systems are the same under DMC point of view.
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