ASD's Blueprint for Secure Cloud

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.

Estimated reading time: 2 minutes


Turn off plus addressing for your organisationNot checked
Turn on sending from aliasesNot checked


Turn off SMTP AUTH protocol for your organisationChecked
Turn on use of legacy TLS clientsNot checked

Reply-all Storm Protection

Enable reply-all storm protectionChecked
Minimum number of recipients2500
Minimum number of reply-alls10
Block duration6

Message Recall

Enable cloud-based message recallChecked
Allow users to recall messages read by the recipientChecked

Security & Governance




  • None identified

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Acknowledgement of Country icon

Acknowledgement of Country
We acknowledge the Traditional Owners and Custodians of Country throughout Australia and their continuing connections to land, sea and communities. We pay our respects to them, their cultures and their Elders; past, present and emerging. We also recognise Australia's First Peoples' enduring contribution to Australia's national security.

Authorised by the Australian Government, Canberra