Simple question.

We have been asked by a third party to update the CNAME record for a client site, in order to facilitiate email redirects.

My understanding is that this is what MX records are for.

My system refuses to update the CNAME as they've requested as it states that SOA record already exists. Also existing CNAME records are in place (for things like www., etc.) going to the main domain.

The third party wants the CNAME updated to autodiscover.outlook.com. Currently it is simply going to the domain website we host.

I believe they are incorrect in requiring this. Am I right?

1 Answer 1


You are both right and wrong.

For email delivery to work, DNS wise all that is required is a valid MX record (but an A record would work absent an mx record). That only covers the MTA though.

In order for IMAP/POP etc to work, the mail client needs to know the appropriate settings. An autodiscover record linked to an appropriately configured web server makes this a lot easier and would appear to be what is requested.

I note that "autodiscover" should be a subdomain (eg autodiscover.example.com) - so if it already exists the cname should be updated or replaced, and this should not affect anything else A cname for the domain name would be a very bad idea (ie you dont want a cname for example.com), and would likely break stuff. If you already have a cname for example.com you are likely doing it wrong, and autodiscover.example.com will be ignored.

  • 1
    Thanks for the info. It turned out that the 3rd party had not specified the correct subdomain for the CNAME record, and upon doing so everything fell into place. Cheers for your info :-)
    – Martin
    Commented May 4, 2021 at 10:42

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