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MTA Issues with Sender Policy Framework (SPF) Technical Level
  • Scenario A: [Anti-Spam is enabled & SPF is enabled] - Only in a cluster environment.
    Scenario B: [Anti-Spam is disabled & SPF is enabled] - In ALL environments;.
    In both scenarios, the mail is detected as SPAM even though the mail is not SPAM. See these screenshots:
  • Activating SPF when MTA is enabled affects the behavior of the Threat Prevention blades as follows:
    *) Threat Emulation blade:
    MTA produces a "Detect" action instead of a "Prevent" action in case of scanning a malicious file.
    **) Threat Extraction:
    Not Triggered at all.
Scenario A: Anti Spam is enabled and SPF is enabled - Only in cluster environment;

In a Cluster environment, the Sender IP that is sent to the Postfix is “”. Because SPF depends on the Sender IP address & Domains, the SPF considers this email as “Suspected SPAM”, and creates a “Detect” log. In some cases, it blocks the email (depending on the configuration of the SPF in MX record).

The loopback address “” behavior is related to the infrastructure of cluster environment with Anti Spam.
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