Network Implementation Guide › Configuring the NBA › NBA Ignores Already-Processed Emails › How Does this Work?

How Does this Work?

1. Domain written to custom header

   When the NBA detects an email or Webmail, it checks for the presence of a custom header containing details about the originating domain and the ‘policy processed’ status. This header is present in:

   • ‘Blocking notification’ and ‘quarantine notification’ e‑mails generated by the Socket API. The originating domain is specified by the SMTPDNSHostName registry value on the Socket API host machine.
   • Emails released from quarantine by the Quarantine Manager. The originating domain is hard-coded to be the domain of the Quarantine Manager; it cannot be changed.
   • Emails already processed by the Exchange or Domino server agents. The originating domain is specified by the SMTPDNSHostName registry value on the server agent host machine.
   • Emails already processed by the Milter MTA agent. The domain is set by the smtp‑dns‑hostname setting in the wgnmilter.conf configuration file.
2. Domain checked against NBA domain list

   If it detects the custom header in an email or Webmail, it compares the domain details with the domain list specified by the <enterprisednslist> tag in nbapolicy.xml. <enterprisednslist> is described in the section for Settings tags.

   If the domain in the header matches an item in the domain list, the NBA then checks the ‘policy processed’ status. For the emails types listed in step 1 above, the status tells the NBA to ignore these emails.

More information:

Settings Tags