Custom/vanity domain name configuration in Exchange Online

[Haneef Ibn Ahmad]

Currently, when users 'Add account' in Microsoft Outlook 2016, the users are automatically configured (possibly through autodiscovery) to connect to 'https://outlook.office365.com/mapi/nspi/?MailboxId=xxx-yyy-zzz@contoso.com' exchange server.

However, I would like them to be automatically configured to connect through our vanity URL, like 'https://exchange.server.consoto.com/mapi/nspi/?MailboxId=xxx-yyy-zzz@contoso.com'.

And I would like the same with:

1) For SMTP: smtp.contoso.com:587 instead of smtp.office365.com:587

2) For POP, IMAP and Exchange Online: exchange.server.contoso.com instead of outlook.office365.com (with the respective ports)

3) For OWA: https://outlook.contoso.com/owa/ instead of https://outlook.office.com/owa/

How can this be configured?

Thanking you,

[#2]

Such configuration is only possible if you are using on-premises Exchange server. In Exchange Online the endpoints are fixed and you cannot change them. You can easily create a solution for #3 though, by creating  CNAME with the corresponding value and using it to redirect to the O365 OWA endpoint.