More than one Edge server must be deployed.

To ensure hostile insiders are unable to easily commit DoS attacks and reduce the effectiveness of mail flow throughout the environment, a second Edge server is deployed to allow for multiple paths of mail flow both internally and externally into the environment. This prevents a single point-of-failure and allows for service to continue in the event of a DoS attack targeting one Edge role.

Review the EDSP for current configuration.

On the mailbox server, open a PowerShell prompt and run the following command:

Get-EdgeSubscription

If there is only one subscription on each server, this is a finding.

At a minimum, a second server must be deployed and subscribed to.