Exchange Online
This section describes the configuration of Exchange Online associated with systems built according to guidance in ASD's Blueprint for Secure Cloud.
Estimated reading time: 3 minutes
Instruction
The below pages outline the as built configuration for ASD’s Blueprint for Secure Cloud (the Blueprint) for the Microsoft Exchange admin portal at the following URL:
https://admin.exchange.microsoft.com/
The settings described on these pages provide a baseline implementation for a system configured using the Blueprint. Any implementation implied by these pages should not be considered as prescriptive as to how an organisation must scope, build, document, or assess a system.
Implementation of the guidance provided by the Blueprint will differ depending on an organisation’s operating context and organisational culture. Organisations should implement the Blueprint in alignment with their existing change management, business processes and frameworks.
When using automated configuration files, organisations should note they will configure the relevant settings in a Microsoft 365 tenancy exactly as outlined in the Configuration pages of the Blueprint. Organisations should ensure they customise configuration of their Microsoft 365 tenancies in accordance with their own design decisions and requirements, deviating from the Blueprint (including automated configuration files) where appropriate.
Placeholders such as <ORGANISATION.GOV.AU>
, <BLUEPRINT.GOV.AU>
and <TENANT-NAME>
should be replaced with the relevant details as required.
Automated Configuration Deployment and Assessment
Overview
Some of the Exchange Online configurations can be automatically deployed using Microsoft 365 Desired State Configuration (DSC).
Some of the Exchange Online configurations cannot be assessed using a DSC blueprint. Please refer to those configuration pages to conduct a manual assessment.
Configuration | Blueprint automation provided |
---|---|
Mail Flow | |
- Rules | Yes (DSC)1 |
- Remote Domains | Yes (DSC) |
- Connectors | No |
Roles | Yes (DSC) |
Settings | No |
1: The words or phrases setting in the Require TLS for sensitive items rule must be configured manually. Refer to Rules for configuration guidance.
Desired State Configuration
Before using the below DSC file, please refer to the automated deployment page for instructions.
Warning
Any existing settings in a tenancy that match the name or UID of any settings in the DSC will be overwritten.
Desired State Configuration file |
---|
Download Exchange Online DSC (.ps1) The linked .txt file must be renamed to .ps1 |
Configuration Data File: |
The configuration data file can be found on the DSC setup page. |
The downloaded DSC file requires the following parameters to be populated or you will be prompted for on import:
Parameter name | Contents |
---|---|
JournallingReportMailbox | Name of an existing mailbox used for sending journalling reports1 |
1: This parameter is only required to import DSC, related journalling configuration settings are not provided.
Service Principal permissions
For organisations importing the DSC as per the instructions on the automated deployment page, the following permissions will need to be added to the Service Principal:
"EXOOwaMailboxPolicy", "EXORemoteDomain", "EXOTransportConfig", "EXOTransportRule"
Additional configuration
The following instructions must be completed before step 6 Deploy the configuration, on the automated deployment page:
- Assign the Entra, Exchange Administrator role to the M365DSC service principal.
Mail Flow
This section describes the configuration of mail flow within Exchange Online associated with systems built according to guidance in ASD's Blueprint for Secure Cloud.
Roles
This section describes the configuration of roles within Exchange Online associated with systems built according to guidance in ASD's Blueprint for Secure Cloud.
Settings
This section describes the configuration of Exchange Online associated with systems built according to guidance in ASD's Blueprint for Secure Cloud.
External Configuration
This section describes the configuration of Exchange Online associated with systems built according to guidance in ASD's Blueprint for Secure Cloud.