I'm confused by Marketo's message about the need to Configure Protocols for Marketo - primarily DMARC
When I logged into the Marketo instance of one of my clients today a message popped up that said something about the need to make changes soon (the pop-up disappeared when I clicked for details - sorry to be so vague). The details page led to this page and I'm confused about what we may or may not have to do and would appreciate clarifiication:
Configure Protocols for Marketo Engage
https://experienceleague.adobe.com/docs/marketo/using/getting-started-with-marketo/setup/configure-protocols-for-marketo.html
As far as I can see, we are already set with regard to Steps 1-3. These things were configured years ago when we initially launched Marketo. I have never seen a Marketo instance that didn't have a CNAME configured for use in landing page URLs, so that the landing pages appear in URLs that reflect the company's domain and not Marketo - though I gather from all the announcements that such instances exist.
Is there anything I should be double-checking with regard to Steps 1-3?
Where I could particularly use advice is with regard to Step 4 - Set Up DMARC. I am unfamiliar with DMARC. Is it strongly recommended that we set this up? If so, which of the two types of alignment for DMARC should we use - DKIM alignment or SPF alignment? How would we decide? I'm struggling to understand this.
Thanks for any insights!