# Create DLP Gateway exception mail flow rule(s) in Exchange Online

## Introduction

This page covers the configuration of additional mail flow rules in Exchange Online to exclude certain email traffic from being routed to the Zivver DLP Gateway.

Excluding these emails is required for messages originating from the Zivver Platform. These should not be rerouted to the Zivver Platform, but delivered within Exchange. Without excluding these emails, they could enter a loop and result in a bounce.

## Getting started

1. Go to the [Exchange Admin Center](https://admin.exchange.microsoft.com/).
2. Click on _mail_outline_ **Mail flow** in the menu on the left.
3. Click on **Rules**.
4. Click on the _add_ **Add a rule** button.
5. Click on **Create a new rule**.
6. Enter `Zivver: Detect processed messages` for the name.

## Set mail flow rule conditions

7. Under **Apply this rule if \*** select **The message headers…**.
8. Under **Select one** select **matches these text patterns**.
9. Click the **Enter text** field.
10. Set the message header to `X-Zivver-Transport`.
11. Click Save.
12. Click the **Enter words** field.
13. Set the value to `..*.` (that is 2 dots, 1 asterisk/wildcard, 1 dot).
14. Click Add.
15. Click Save.

## Set mail flow rule actions

16. Under **Do the following \*** select **Modify the message properties**.
17. Under **Select one** select **set a message header**.
18. Click the first **Enter text** field.
19. Set the message header to `skip-zivver-relay`.
20. Click Save.
21. Click the second **Enter text** field.
22. Set the value to `true`.
23. Click Save.
24. Click Next.

## Set rule settings

25. Leave the **Rule mode** on the default setting of **Enforce**.
26. Leave the **Severity** on the default setting of **Not specified**.
27. _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.
28. Leave **Deactivate this rule on** disabled.
29. Leave the option **Stop processing more rules** disabled.
30. Leave the option **Defer the message if rule processing doesn’t complete** disabled.
31. Leave **Match sender address in message** to the default setting of **Header**.
32. Enter the following text in the **Comments** section:

```plain
    Exclude messages that have been processed and sent by the Zivver Platform to avoid mail looping.
    ```

33. Click Next.

## Review and finish

34. When you are satisfied that the mail flow rule is configured correctly, click Finish.

## Set the priority

35. Ensure the mail flow rule has a higher priority than the primary DLP Gateway mail flow rule configured in Part 1.

## Activate the rule

After creating and correctly setting the priority of the rule, it can be enabled.
See [Enable Primary DLP Gateway mail flow rule in Exchange Online](https://docs.zivver.com/en/admin/smtp/enable-primary-dlp-mail-flow-rule-online.html) for instructions on activating the rule.

## Repeat steps for X-Zivver-DLP header

If your organization also uses a Zivver client integration (such as Zivver for Outlook or Zivver for Gmail), this additional exception is strongly advised for emails that have been scanned by a Zivver client integration and for which the user decided not to activate Zivver. These can be excluded from being routed to the DLP Gateway, because the DLP Gateway may end up overruling the user’s decision, causing unwanted and unexpected behavior.

36. Repeat all steps above with the following changes:
37. Name the rule `Zivver: Detect messages scanned by client integration`.
38. Substitute the **X-Zivver-Transport** header with the **X-Zivver-DLP** header wherever it occurs.
39. Include an exception with the following steps:
    1. Under **Except if**, select **The subject or body**.
    2. Under **Select one**, select **subject matches these text patterns**.
    3. Enter `(?i)\[secure\]` in the input field.
    4. Click Add.
    5. Click Save.
40. Enter the following text in the **Comments** section:

```plain
    Exclude messages that have already been scanned by a Zivver client integration to avoid DLP Gateway overruling user decisions or making a suggestion that was already provided while the message was composed.
    ```

## Next step

Go back to [Setup DLP Gateway](https://docs.zivver.com/en/admin/smtp/setup-dlp-gateway.html) and continue with Part 3.

Updated on 2026-06-18