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

## Introduction

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

Excluding these emails is required for messages originating from the Zivver Platform. They should be delivered within Exchange rather than being rerouted back to the Zivver Platform, as this could cause loops and result in bounces.

## Getting started

1. Go to the Exchange Admin Center (EAC).
2. Log in to the EAC as an administrator.
3. Click on **Mail flow** in the menu on the left.
4. Click on **Rules**.
5. Click on the _add_ icon.
6. Click on **Create a new rule...**.
7. Enter `Zivver: Detect processed messages` as the name.
8. At the bottom of the page, click on **More options...**.

## Set mail flow rule conditions

9. Under **\*Apply this rule if...**, select **The message headers ...** and then **matches these text patterns**.
10. Click the **\*Enter text...** field.
11. Set the message header to `X-Zivver-Transport`.
12. Click OK.
13. Click the **\*Enter text patterns...** field.
14. Enter the value `..*.` (that is 2 dots, 1 asterisk/wildcard, 1 dot).
15. Click the _add_ icon.
16. Click OK.

## Set mail flow rule actions

17. Under **\*Do the following...**, select **Modify the message properties...** and then **set a message header**.
18. Click the first **\*Enter text...** field.
19. Set the message header to `skip-zivver-relay`.
20. Click OK.
21. Click the second **\*Enter text...** field.
22. Set the value to `true`.
23. Click OK.

## Set rule settings

24. Leave the **Audit this rule with severity level** on the default setting of **Not specified**.
25. Leave the **Choose a mode for this rule** on the default setting of **Enforce**.
26. _Optional_: Enable **Activate this rule on the following date** and select a date and time if you want this mail flow rule to be automatically activated from a specific date and time.
27. Leave **Deactivate this rule on the following date** disabled.
28. Leave the option **Stop processing more rules** disabled.
29. Leave the option **Defer the message if rule processing doesn’t complete** disabled.
30. Leave **Match sender address in message:** on the default setting of **Header**.
31. 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.
```

30. When you are satisfied that the mail flow rule is configured correctly, click Save.

## Set the priority

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

## 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), applying this additional exception is strongly advised for emails that have been scanned by a Zivver client integration and for which the user has decided not to activate Zivver. These emails can be excluded from being routed to the DLP Gateway, because the DLP Gateway might otherwise override 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...**, click the add exception button.
    2. Select **The subject or body...** and then **subject matches these text patterns**.
    3. Enter `(?i)\[secure\]` in the input field.
    4. Click on the _add_ icon.
    5. Click OK.
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