Forum Discussion

Copper Contributor

Sep 05, 2023

External DNS records required for email in Office 365 (Exchange Online)

Hi all, we have a configuration with an OnPrem Exchange Server 2019 Infra in hybrid with Exchange Online. Looking at the MS documentation avaliable at this link: External Domain Name System records...

Copper Contributor

Sep 06, 2023

Hi elieelkarkafi, thanks for your reply.

The configuration of the autodiscover service in a hybrid configuration is clear.

I'm specifically referring to the CNAME record autodiscover.service.contoso.com (where contoso.com is your mail domain) only.

What's the scope of this record? And in which scenario is configured?

elieelkarkafi

MVP

Sep 06, 2023

autodiscover allows outlook to automatically detect the user mailbox settings without manual intervention, if you're in hybrid mode and you still have mailboxes on-premises you need to point your Autodiscover record to on-premises.

LoremanReturns9791
Copper Contributor
Sep 06, 2023
you didn't replied to my question. Anyone can clarify the scope of autodiscover.service.contoso.com CNAME record? Thanks
- elieelkarkafi
  MVP
  Sep 06, 2023
  this CNAME record is used only if your company is using Exchange federation.
  - LoremanReturns9791
    Copper Contributor
    Sep 06, 2023
    you're mentioning what can be found in the documentation i linked in my first post, this is not useful.
    In a Hybrid Configuration Exchange OnPrem and Exchange Online are federated. Does this mean that this CNAME record is recommended? If yes: is it recommended also if part of mailboxes are online and part are onprem? Which is the configuration seggested for the record? Must it point to autodiscover.outlook.com?
    Thanks