Order of Filter Rules

The filter rules of the Compliance Filter are processed in a defined sequence.

Important:

Please notice how the Compliance Filter ranks in the order of our services (see Ruleset Order). Once a rule of one of the services matches an email, the processing of other rules is stopped. No other rules are applied to the email.

This order allows you to create exceptions for Content Control with filter rules of the Compliance Filter that categorize emails as Clean.

The filter rules of the Compliance Filter are processed according to their criteria in the following sequence:

  1. Body
  2. Header
  3. Advanced
Figure 1: Order of filter rules by criterion

Within a criterion, the filter rules of the Compliance Filter are ranked according to their priority.

Note:

The higher the number, the lower the priority of the filter rule.

You can change the priority of a filter rule (see Changing the Priority of a Filter Rule).

The following examples illustrate the order in which the rules are processed.

Simple processing of filter rules

Initial situation:

You have defined filter rules for the Compliance Filter. No rules of other services apply to this case.

Figure 2: Filter rule: Forward

Procedure:

  1. An email from invoice@creditor.com is sent to any user of the domain debitor.com.
  2. The Compliance Filter first searches the filter rules with the criterion Body, then the filter rules with the criterion Header and finds a match in the filter rules with the criterion Advanced.
  3. The filter rule is applied. The Compliance Filter does not search for any other matches in other filter rules.

Conflict between several filter rules with the same criterion

Initial situation:

You have defined two different filter rules with the criterion Advanced for the Compliance Filter for the event that an outgoing email is sent to sales@creditor.com. Both filter rules cause a BCC to be added to the email. For one filter rule the BCC recipient is purchasing@creditor.com, for the other one it is ceo@creditor.com. The filter rule with the BCC recipient purchasing@creditor.com has a higher priority than the filter rule with the BCC recipient ceo@creditor.com, and is listed above the other filter rule in the overview of filter rules. No other filter rules apply to this case.

Figure 3: Filter rule: add purchasing@creditor.com as BCC recipient
Figure 4: Filter rule: add ceo@creditor.com as BCC recipient
Figure 5: Order of Filter Rules

Procedure:

  1. An email from any sender is sent to sales@creditor.com.
  2. The Compliance Filter first searches the filter rules with the criterion Body, then the filter rules with the criterion Header and finds a match in the filter rules with the criterion Advanced.
  3. The filter rule with the higher priority (BCC to purchasing@creditor.com) is applied. The Compliance Filter does not search for any other matches in other filter rules. The filter rule with the lower priority (BCC to ceo@creditor.com) is not applied.

Conflict between rules with different criteria

Initial situation:

You have defined a filter rule establishing that incoming emails with a link to Facebook should be categorized as Spam. In another filter rule, you have defined an exception for the recipient marketing@debitor.com. The exception causes emails sent directly from Facebook to marketing@debitor.com to be categorized as Clean. The filter rule with the exception for marketing@deditor.com has a higher priority than the filter rule for emails with links to Facebook, and is listed above the other filter rule in the overview of filter rules. No other filter rules apply to this case.

Figure 6: Filter rule: Tag as clean
Figure 7: Filter rule: Tag as spam
Figure 8: Order of Filter Rules

Procedure:

  1. Facebook sends an email with a link to marketing@debitor.com.
  2. The Compliance Filter first searches the filter rules of the criterion Body and finds a match in the filter rule for emails that contain links to Facebook.
  3. The filter rule is applied to the email and the email is categorized as Spam. The Compliance Filter does not search for any other matches in other filter rules. Despite its higher priority, the filter rule with the exception for marketing@debitor.com is not applied because the filter rules with the criterion Body take precedence over the filter rules of the other criteria.

Conflict between the Compliance Filter and our filter rules

Initial situation:

Due to a high spam volume from one IP address, you have defined a filter rule establishing that emails from this IP address should be tagged as spam. No other filter rules of the Compliance Filter apply to this case. In addition to the filter rule of the Compliance Filter, a filter rule defined by us applies to this case.

Figure 9: Filter rule: Tag emails from an IP address as spam

Procedure:

  1. A sender from the domain behind the IP address sends an email to any recipient.
  2. The Compliance Filter first searches the filter rules with the criterion Body, then the filter rules with the criterion Header and finds a match in the filter rules with the criterion Advanced.
  3. The filter rule is applied to the email and the email is categorized as Spam. The Compliance Filter does not search for any other matches in other filter rules.
  4. We have already defined a more precise filter rule for this case. The high spam volume could be narrowed down to the sender info@. Other email addresses of the domain do not send any spam emails. Because our filter rules are not searched anymore, your own filter rule, the scope of which is too extensive, is applied. A clean email could thus be tagged as spam.