# Mimecast Secure Email Gateway

## Introduction

This manual describes how to integrate Zivver with the Mimecast Secure Email Gateway.

Mimecast provides a Secure Email Gateway (SEG) solution that protects organizations against email-based threats, such as phishing and ransomware. Zivver helps organizations prevent data leaks via email.

Organizations often want to combine Zivver and Mimecast’s Secure Email Gateway to benefit from both solutions. Read more about how Zivver and Mimecast compare in the Feature Gap Analysis, available on request via [sales@zivver.com](mailto:sales@zivver.com).

The starting point for integrating Zivver with the Mimecast Secure Email Gateway is the Zivver Office Plugin for Microsoft Outlook (Windows). Read more about this in the next section.

## Zivver’s Plugin Assisted Mail Submission

With the Zivver Office Plugin for Microsoft Outlook (Windows), employees can send and receive secure messages directly from within Outlook.

Zivver’s Plugin Assisted Mail Submission (PAMS) is an additional feature in the Zivver Office Plugin. PAMS can be used for different purposes; see the [PAMS manual](https://docs.zivver.com/en/admin/officeplugin/pams/introduction.html) for more information.

To integrate Zivver with the Mimecast Secure Email Gateway, your organization must implement PAMS. PAMS enables Mimecast’s Secure Email Gateway to process outbound Zivver messages sent from Outlook. Without PAMS, a sent Zivver message will not be processed by Mimecast.

## Background information

When a secure Zivver message is sent, the Zivver Office Plugin for Outlook cancels the OnSend event for that message. If Outlook does not cancel the event, the message is passed to the mail server and delivered as a normal, unsecured message. To prevent this, the plugin cancels the OnSend event.

However, when using Mimecast’s Secure Email Gateway, you want the securely sent Zivver message to be processed by the mail server and Mimecast. PAMS ensures that the OnSend event is still triggered, allowing Mimecast to process the securely sent message.

To prevent the securely sent message from being delivered as a normal email, Mimecast must submit the message to the Zivver SMTP Gateway.

## Implement PAMS in Mimecast Secure Email Gateway

This chapter describes what is required to implement PAMS in the Mimecast Secure Email Gateway. In short, Mimecast must filter outbound messages on a custom mail header. When this header is found, the message must be submitted to the Zivver SMTP Gateway.

Once received at Zivver’s SMTP Gateway, the message is processed and securely delivered to the recipients.

In Mimecast, the following two steps must be performed:

- Create a connection to the Zivver SMTP Gateway.
- Filter outbound messages on a custom mail header.

### Create an outbound Delivery routing definition to connect to the Zivver SMTP Gateway

01. Log in to the [Zivver WebApp](https://app.zivver.com/).
02. Click **Organization Settings**.
03. Expand **Integrations**.
04. Click **SMTP credentials**.
05. Click  New SMTP credentials to generate SMTP credentials.
06. Go to your **Mimecast Administration Console**.
07. Go to **Administration > Gateway > Policies > Delivery routing – Definitions**.
08. Select or create a new policy.
09. Enter a **Description** (e.g., Zivver SMTP Server).
10. For **Hostname**, enter: `smtp.zivver.com`.
11. For **Port**, enter: `587`.
12. For **Enable SMTP Authentication**, select **Login**.
13. For **Username**, enter the username from the generated SMTP credentials + `@smtp.zivver.com`.

_Example: 0dbaec1b-XXXX-XXXX-acXX-804f1dXXXXX@smtp.zivver.com_
14. For **Password**, enter the generated password.
15. Click **Save** and **Exit**.

### Filtering outbound messages on a custom mail header

Two configurations must be set in Mimecast to filter outbound messages on the custom mail header used by the Zivver Office Plugin to mark a message for PAMS:

- A Content Examination definition.
- A Content Examination policy.

#### Create a Content Examination definition

16. Go to your **Mimecast Administration Console**.
17. Go to **Administration > Gateway > Policies**.
18. Go to **Content Examination**.
19. Click **Definitions**.
20. Select the group you want to change.
21. Click **New Content Definition**.
22. Enter a **Description** (e.g., Zivver PAMS).
23. For **Definition Type**, select **Independent Content Definition**.
24. Set the **Activation Score** to 1.
25. For **Fuzzy Hash Setting**, select **Do not use Fuzzy Hash techniques**.
26. For **Word / Phrase Match List**, enter: `1 "zivver-relay"`.
27. Enable **Scan Message Headers**.
28. Enable **Enable Inbound and Outbound check**.
29. For **Policy Action**, select **None**.
30. For **Delivery Route**, select the previously created **Delivery Route definition**.
31. Click **Save** and **Exit**.

#### Create a Content Examination policy

32. Go to your **Mimecast Administration Console**.
33. Go to **Administration > Gateway > Policies > Content Examination**.
34. Click the name.
35. Select or create a new policy.
36. Enter a **policy narrative** (e.g., Zivver PAMS).
37. Select the **Content Examination Definition** you created earlier.
38. For **Addresses Based On**, select **Both**.
39. For **Applies From / To**, select **Internal addresses only**.
40. Enable the policy.
41. Click **Save** and **Exit**.

### Additional change to the mail server

Many organizations have a Mail Flow Rule in Exchange that relays any externally addressed outbound message to Mimecast. Internal messages normally do not need to be processed by Mimecast.

However, when integrating Zivver with Mimecast, securely sent messages to internal recipients must also be processed by Mimecast. Otherwise, these messages are not relayed to Zivver, and internal recipients will not be part of the secure conversation.

To ensure securely sent messages are always relayed to the Zivver SMTP Gateway, create a Mail Flow Rule that filters securely sent messages to internal recipients.

01. Go to the [Exchange Admin Center](https://admin.exchange.microsoft.com/).
02. Click _mail_outline_ **Mail flow** in the left menu.
03. Click **Rules**.
04. Click _add_ **Add a rule**.
05. Click **Create a new rule**.
06. Give the rule a name (e.g., Routing securely sent internal mail to Zivver).
07. Under **Apply this rule if \***, select **The message headers…**.
08. Under **Select one**, select **matches these text patterns**.
09. In **Enter text**, enter `zivver-relay`.
10. Click Save.
11. In **Enter words**, enter `..*.` (two dots, one asterisk, one dot).
12. Click Add.
13. Click Save.
14. Click **+** to add a second condition.
15. Under **And**, select **The sender**.
16. Click **Select one** and select **is external/internal**.
17. Select **Inside the organization**.
18. Click Save.
19. Under **Do the following \***, select **Redirect the message to**.
20. Click **Select one** and select **the following connector**.
21. Select the connector used to relay the message to Mimecast.
22. Click Save.
23. Click Save.
24. Ensure this rule is processed after the external outbound rule for Mimecast.
25. Enable the rule when ready.

Updated on 2026-06-18