to authenticate outbound email with these protocols, you need to set up SPF, DKIM, and DMARC for your domain.

To set up SPF, DKIM, and DMARC for your domain, follow these steps:

1. Set up SPF (Sender Policy Framework):
   • Create an SPF TXT record in your DNS zone file that lists the IP addresses authorized to send emails on behalf of your domain. This helps prevent email spoofing.
   • For detailed instructions, refer to the article on setting up SPF for custom domains in Microsoft 365.
2. Set up DKIM (DomainKeys Identified Mail):
   • Generate a DKIM key pair and add a DKIM record to your DNS zone file. This ensures that your emails are sent by an authorized sender and that the content hasn't been tampered with.
   • You can find more information on configuring DKIM in the relevant Microsoft documentation.
3. Set up DMARC (Domain-based Message Authentication, Reporting, and Conformance):
   • Create a DMARC TXT record in your DNS that specifies the action to take for messages that fail SPF or DKIM checks. Start with a policy of p=none to monitor results before moving to p=quarantine or p=reject.
   • For guidance on setting up DMARC for your custom domains, refer to the related Microsoft documentation.

It's recommended to implement these protocols in a gradual manner, starting with monitoring before enforcing stricter policies to avoid blocking legitimate emails.

References:

• Set up SPF to identify valid email sources for your custom cloud domains
• Set up DKIM to sign mail from your cloud domain
• Set up DMARC to validate the From address domain for cloud senders