SMTP clients can connect to Microsoft Online SMTP servers and authenticate using a Microsoft Online Services user credentials to send mail. The connection requires Transport Layer Security (TLS). This allows you to use Exchange Online as an SMTP service for mail originating outside of the Exchange Online environment, but routed by Exchange Online.

To connect to the Microsoft Online Services SMTP server, open your SMTP client application and provide the information below.

o    The fully qualified domain name (FQDN) of the Microsoft Online Services SMTP server. The FQDN will be slightly different depending on which Microsoft Online Services datacenter your company is connected to. The server FQDNs are:

o    North America Datacenter:  Smtp.mail.microsoftonline.com

o    Europe Datacenter:  Smtp.mail.emea.microsoftonline.com

o    Asia Pacific Datacenter:  Smtp.mail.apac.microsoftonline.com

o    The user name and password of a Microsoft Online Services user account with an Exchange Online license.

• On most client applications, this is under “My outgoing mail server (SMTP) requires authentication” – this should be configured “Yes”, and the corresponding Microsoft Online username and password supplied.

o    The SMTP port to use: 587.

• On most client applications, this is under “Server Port Numbers for Outgoing Server (SMTP)” – this should be configured to use port 587

o    Make sure that Transport Layer Security (TLS) is enabled in your SMTP client.

• On most client applications, this is under “My outgoing mail server (SMTP) requires an encrypted connection (SSL)” – this should be configured “Yes”

NOTE:  The FROM address must use a SMTP domain of type “Authoritative” – this can be

confirmed in Microsoft Online Administration Console, under the Users - Domains tab.

Important: Remember to update the user Microsoft Online Account password regularly, before it expires or your service will be unable to connect.