Document information

Document ID:4651
Subject:Custom filter for inconsistent sender
Creation date:12/14/15 4:35 PM
Last modified on:12/14/15 4:35 PM

Inconsistent senders

Sender's email address is sent in twice by the sender SMTP server. The first time it appears in the SMTP communication (RFC 821) and the second time it appears in the email envelope (RFC 822).

Often spammers specify a different address in the first step to prevent SPF detection. Using this rule Xeams can identify if such trick is used.

IMPORTANT: This rule only applies if SPF is used for the sender's domain name. When SPF is not used, this rule does not have affect.

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