Create primary DLP Gateway mail flow rule in Exchange Online

Introduction

This page covers the configuration of the primary mail flow rule for DLP Gateway in Exchnage Online, which will be responsible for routing selected email traffic to Zivver.

Getting started

  1. Go to the Exchange Admin Center.
  2. Click on Mail flow in the menu on the left.
  3. Click on Rules.
  4. Click on add Add a rule.
  5. Click on Create a new rule.
  6. Enter a name. For example: Zivver DLP Gateway

Set mail flow rule conditions

  1. Under Apply this rule if * select The sender.
  2. Under Select one select is external/internal.
  3. In the side pane that opens, select Inside the organization.
  4. Click Save.
  5. Add any other conditions you want to be satisfied for emails to be routed to Zivver DLP Gateway.
In case of a phased or partial roll-out of DLP Gateway, you can configure conditions based on sender characteristics, e.g. specific users, user groups, or email domains. Further information from Microsoft on mail flow rule conditions can be found here.
Any conditions you apply must apply to the entire message, not to any recipients of the message. Conditions applied on recipient level will lead to only the message to the recipient(s) matching the conditions being relayed to Zivver, resulting in split conversations.

Set mail flow rule actions

  1. Under Do the following * select Modify the message properties.
  2. Under Select one select set a message header.
  3. Click the first Enter text field.
  4. Set the message header to zivver-relay.
  5. Click Save.
  6. Click the second Enter text field.
  7. Set the value to smart.
  8. Click Save.
  9. Click the add button to the right of set a message header.
  10. Under And select Redirect the message to.
  11. Under Select one select the following connector.
  12. Select the connector that you have previously created for Zivver.
  13. Click Save.

Set mail flow rule exceptions

  1. Under Except if select The message headers….
  2. Under Select one select matches these text patterns.
  3. Click the Enter text field.
  4. Set the message header to skip-zivver-relay.
  5. Click Save.
  6. Click the Enter words field.
  7. Set the value to ..*. (that is 2 dots, 1 asterisk/wildcard, 1 dot).
  8. Click Add.
  9. Click Save.
  10. Click Next.
If there are any further exclusions from DLP Gateway related to a phased/partial roll-out of DLP Gateway and/or specific to your organization, you can configure additional exceptions. Further information from Microsoft on mail flow rule exceptions can be found here.

Set rule settings

  1. Leave the Rule mode on the default setting of Enforce.
  2. Leave the Severity on the default setting of Not specified.
  3. Optional: Enable Activate this rule on and select a date and time, if you want this mail flow rule be automatically activated from a specific date and time.
  4. Leave Deactivate this rule on disabled.
  5. Enable the option Stop processing more rules.
  6. Enable the option Defer the message if rule processing doesn’t complete.
  7. Leave Match sender address in message to the default setting of Header.
  8. Leave the Comments section blank, unless otherwise desired.
  9. Click Next.

Review and finish

  1. Carefully review all rule conditions, actions, exceptions and settings. Any errors in mail flow rule configuration may result in delivery issues of outbound emails.
  2. When you are satisfied that the mail flow rule is configured correctly, click Finish

Modify the priority of the mail flow rule, if needed

Make sure that the priority of all the existing rules is correct. If other rules must process a message first, make sure that the Primary DLP Gateway rule has a lower priority. Also, make sure that the other rules with a higher priority do not have the setting ‘Stop processing other rules’ enabled, unless you explicitly want messages that trigger this/these rule(s) not to be processed by DLP Gateway.
  1. If you need to adjust the priority of the mail flow rule, find the mail flow rule you have created in the overview on the Rules page
  2. Check the checkbox to the left of Disabled and use the Move up or Move down buttons to move the mail flow rule up or down into the correct order of priority.
  3. Alternatively, click the name of the mail flow rule. In the side pane which opens, select Edit rule settings. Then, under Priority, enter the correct priority for the mail flow rule. Then click Save and wait for the setting to be saved.

Next step

Go back to Setup DLP Gateway and continue with Part 2.

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