Custom made rule that checks a dictionary of allowed emails is not triggering as expected

Products

• Messaging Gateway

Issue/Introduction

You have created a custom content filtering rule that tests "Text in the specific part of the message header", either "Envelope sender" or "Envelope recipient", using a dictionary of email addresses to match and the rule does not trigger as expected.

Resolution

1. Dictionary Match Requirements

Dictionary matches in SMG for email addresses are exact string matches.

• No Wildcards: You cannot use*@example.comorexample.comin a dictionary to match users from a domain. You must enter the full, specific email address (e.g.,[email protected]).
• Case and character Sensitivity: While email addresses are generally case-insensitive in routing, ensure there are no leading/trailing spaces or hidden characters in your dictionary entries.
• Envelope vs. Header: Ensure your rule condition matches the correct part of the message. Dictionary items match against the SMTP handshake's "Envelope Sender", which is generally more reliable than the "From:" header, as the header can be spoofed.

3. Rule Order and Precedence

SMG processes content filtering rules in order from top to bottom and bypass logic may impact full evaluation.

• Competing Rules: Check if there is another rule higher in the list that is affecting the end result. If a higher-priority rule triggers and has bypass logic, your email address dictionary rule might never be evaluated.

4. Message flow direction

• Transaction and rule direction: Messaging Gateway content filter rules specify whether the rule is to apply to Inbound, Outbound, or "Inbound and outbound" messages. If the message is not flowing in the direction that the rule has specified for evaluation, the rule will not be evaluated. The direction for a rule can be seen in the "Applied To" column of the Email Content Filtering Policies page, and the direction of a specific transaction can be seen in the Message Audit Log for that specific message transaction.

When you have confirmed that your dictionary items meet requirements and the rule is fully evaluating against a matching address, you will see the rule trigger.