Policies - Metadata Preservation Policy

In this article, you will learn about the Metadata Preservation policy and how it is configured. Message metadata is limited to a value less than your Maximum Account Retention setting by the Metadata Preservation Policies. Email metadata (including the header) is the associated information present in a message, including:

• Date and time stamps
• Mail server information
• From / To addresses
• Subject
• Message-id

There are two versions of the policy, the only difference between them being the length of time that messages are stored:

• Metadata Preservation (Days): Specifies the number of days that the metadata is retained.
• Metadata Preservation (Minutes): Specifies the number of minutes that the metadata is retained.

Usage Considerations

Consider the following before configuring a policy:

• An Accepted Message is not archived, if it has a retention period of three days or less. Instead, it remains in the Accepted Messages queue until it expires. We also retain additional metadata information (e.g., policies applied to the message, delivery, and rejection details).
• Message retention can be adjusted using Retention Adjustments.
• Metadata Preservation (Minutes) policies are applied after indexing is complete. For example, if a policy is configured to purge data after five minutes but indexing is not complete, the data is purged five minutes after indexing finishes.
• Metadata Preservation policies are applied to mail items and not mailboxes. This means that if there are two policies with different retention periods, and an email is sent to multiple users covered by different policies with different retention periods, the policy with the longer retention period is applied. This is regardless of whether the policy relevant to the user has a shorter retention period.

The Metadata Preservation policy always needs to be equal to or higher than the Content Preservation policy, as the metadata is required to search for and/or view the content.

Configuring a Metadata Preservation (Days or Minutes) Policy

To configure a Metadata Preservation (Days or Minutes) policy:

1. Log in to the Mimecast Administration Console.
2. Select the Policies | Gateway Policies menu item.
3. Either select:

• • • Metadata Preservation (Days) to configure a Days policy.
    • Metadata Preservation (Minutes) to configure a Minutes policy.

4. Either select the:

• • • Policy to be changed.
    • New Policy button to create a policy.

5. Complete the Options section as required:

Field / Option	Description
Policy Narrative	Provide a description for the policy to allow you to easily identify it in the future.
Preservation Time (Days or Minutes)	Specify the number of days or the number of minutes, depending on your chosen policy. This is based on the sent date of the message and determines the length of time that the metadata of the message is stored in the Archive. This policy cannot override the maximum Account Retention period, and can only be used for a subset of users.

6. Complete the Emails From and Emails To sections as required:

Field / Option	Description
Addresses Based On	Specify the email address characteristics the policy is based on. This option is only available in the Emails From section. The options are: The Return Address (Mail Envelope From): This default setting applies the policy to the SMTP address match, based on the message's envelope or true address (i.e., the address used during SMTP transmission). The Message From Address (Message Header From): Applies the policy based on the masked address used in the message's header. Both: Applies the policy based on the Mail Envelope From or the Message Header From, whichever matches. If both match the specified value, the Message Header From is used.
Applies From / To	Specify the Sender characteristics that the policy is based on. For multiple policies, you should apply them from the most specific to the least specific. The options are: Everyone: Includes all users (i.e., internal and external). This option is only available in the Emails From section. Internal Address: Includes only internal organization addresses. External Address: Includes only external organization addresses. This option is only available in the Emails From section. Email Domain: Enables you to specify a domain name to which this policy is applied. The domain name is entered in the Specifically field. Address Groups: Enables you to specify a directory or local group. If this option is selected, click on the Lookup button to select a group from the Profile Group field. Once a group has been selected, you can click on the Show Location field to display the group's path. Address Attributes: Enables you to specify a predefined Attribute. The attribute is selected from the Where Attribute drop-down list. Once the Attribute is specified, an attribute value must be entered in the Is Equal To field. This can only be used if attributes have been configured for user accounts. Individual Email Address: Enables you to specify an SMTP address. The email address is entered in the Specifically field.

7. Complete the Validity section as required:

Field / Option	Description
Enable / Disable	Use this to enable (default) or disable a policy. If a date range has been specified, the policy will automatically be disabled when the end of the configured date range is reached.
Set Policy as Perpetual	If the policy's date range has no end date, this field displays Always On, meaning that the policy never expires.
Date Range	Use this field to specify a start and/or end date for the policy. If the Eternal option is selected, no date is required.
Policy Override	This overrides the default order in which policies are applied. If there are multiple applicable policies, this policy is applied first unless more specific policies of the same type are configured with an override.
Bi-Directional	If selected, the policy is applied when the policy's recipient is the sender, and the sender is the recipient.
Source IP Ranges (n.n.n.n/x)	Enter any required Source IP Ranges for the policy. These only apply if the source IP address used to transmit the message data falls inside or matches the range(s) configured. IP ranges should be entered in CIDR notation.

8. Click on the Save and Exit button.