How do I use Office365 for SMTP?

How to set up a multifunction device or application to send email using Office 365

This article explains how you can send email from devices and business applications when all of your mailboxes are in Office 365. For example:

  • You have a scanner, and you want to email scanned documents to yourself or someone else.

  • You have a line-of-business (LOB) application that manages appointments, and you want to email reminders to clients of their appointment time.

Option 1 (recommended): Authenticate your device or application directly with an Office 365 mailbox, and send mail using SMTP client submission

This option supports most usage scenarios and it's the easiest to set up. Choose this option when:

  • You want to send email from a third-party hosted application, service, or device.

  • You want to send email to people inside and outside your organization.

To configure your device or application, connect directly to Office 365 using the SMTP client submission endpoint

Each device/application must be able to authenticate with Office 365. It can have its own sender address, or all devices can use one address, such as

How to set up SMTP client submission

Enter the following settings directly on your device or in the application as their guide instructs (it might use different terminology than this article). As long as your scenario meets the requirements for SMTP client submission, the following settings will enable you to send email from your device or application.

Device or Application setting


Server/smart host


Port 587 (recommended) or port 25



Username/email address and password

Enter the sign in credentials of the hosted mailbox being used


Option 2: Send mail directly from your printer or application to Office 365 (direct send)

Choose this option when:

  • SMTP client submission (Option 1) is not compatible with your business needs or with your device. For example, your device or application does not meet the requirements of SMTP client submission, such as TLS support.

  • You only need to send messages to recipients in your own organization who have with mailboxes in Office 365; you don't need to send email to people outside of your organization.

Other scenarios when direct send may be your best choice:

  • You want your device or application to send from each user’s email address and do not want each user’s mailbox credentials configured to use SMTP client submission. Direct send allows each user in your organization to send email using their own address.

    Avoid using a single mailbox with Send As permissions for all your users. This method is not supported because of complexity and potential issues.

  • You want to send bulk email or newsletters. Office 365 does not allow you to do this via SMTP client submission. Direct send allows you to send a high volume of messages.

    Note that there is a risk of your email being marked as spam by Office 365. You might want to enlist the help of a bulk email provider to assist you. For example, they'll help you adhere to best practices, and can help ensure that your domains and IP addresses are not blocked by others on the Internet.


Option 3: Configure a connector to send mail using Office 365 SMTP relay

This option is more difficult to implement than the others. Only choose this option when:

  • SMTP client submission (Option 1) is not compatible with your business needs or with your device

  • You can't use direct send (Option 2) because you must send email to external recipients.

SMTP relay lets Office 365 relay emails on your behalf by using your public IP address (or a certificate) to authenticate Office 365. To do this, you'll need to set up a connector for your Office 365 account, which is what makes this a more complicated configuration.


Compare the options

Here's a comparison of each configuration option and the features they support.


SMTP client submission

Direct send

SMTP relay


Send to recipients in your domain(s)




Relay to Internet via Office 365


No. Direct delivery only.


Bypasses antispam

Yes, if the mail is destined for an Office 365 mailbox.

No. Suspicious emails might be filtered. We recommend a custom Sender Policy Framework (SPF) record.

No. Suspicious emails might be filtered. We recommend a custom SPF record.

Supports mail sent from applications hosted by a third party





Open network port

Port 587 or port 25

Port 25

Port 25

Device or application server must support TLS




Requires authentication

Office 365 user name and password required


One or more static IP addresses. Your printer or the server running your LOB app must have a static IP address to use for authentication with Office 365.


Throttling limits

10,000 recipients per day. 30 messages per minute.

Standard throttling is in place to protect Office 365.

Reasonable limits are imposed. The service can't be used to send spam or bulk mail. For more information about reasonable limits, see Higher Risk Delivery Pool for Outbound Messages.

Use your own email server to send email from multifunction devices and applications

If you have mailboxes in Office 365 and an email server that you manage (also called an on-premises email server), always configure your devices and applications to use your local network and route email through your own email server. For details about setting up your Exchange server to receive email from systems that are not running Exchange (such as a multifunction printer), see Create a Receive Connector to Receive Email from a System Not Running Exchange.

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