Azure Email forwarding for external domain + dkim

Question

We need to be able to send email for xxx@externaldomain.com we also need to apply dkim This domain is already managed by the company that owns it on their Azure account, so azure won't allow us to administer it in any way or add it to domains. Is there a way to add this email for this domain and add Dkim to it? They will add whatever DNS records we need but everything i find relating to sending email for a domain in O365/azure requires authenticating we own the domain and azure won't let two different accounts manage the same domain for any services.

Answer 1

That wont work sending from 365 as you can imagine. You wont be able to send as another domain that isnt your verified and accepted domain.

Answer 2

Your sending infrastructure would need to apply the DKIM headers and hashes and they would simply have a CNAME that points to you in their DNS.
If you cant do that, you may want to look at a 3rd party solution and have them apply DKIM to the messages.

Answer 3

Yes, I just can't find if there is a way to do this, pretty much searching for information and hoping someone out there has done it or knows more than me (not hard).

Answer 4

Third party mailing vendors can definitely do this for you.
If you are sending from your Exchange Server then you would need to route through 365 or a third party mailer.
There are few solutions for Exchange itself

https://dmarcian.com/dkim-dmarc-microsoft-exchange/

Answer 5

So the first part of the issue is that we need to use O365 to manage the email due to the site and other things related being hosted via azure, otherwise i'd just use our postfix server and open dkim. So Third party options weren't really what we wanted.

The second part of the issue is that we need to send mail as xxx@externalcomain.com which doesn't belong to us and is already hosted in azure by it's owner.

The last issue is adding Dkim so we can authenticate.