You should use port 587 as a default smtp port.
Office 365 smtp relay port 587.
The sending app must authenticate with office 365.
Before you attempt to create a connector be sure your account has the proper exchange online permissions.
The sending app must connect to the office 365 servers on port 587.
Microsoft 365 or office 365 smtp relay has higher sending limits than smtp client submission.
Office 365 smtp settings for scanner or application to send an email from your scanner or application you can t always use the first method.
In some cases your applications or devices don t support the requirements for connecting to office 365 using ssl or on the non standard smtp port of 587.
To set up an smtp relay you must first create a connector in office 365 to accept smtp transactions.
Then click on more settings outgoing server to set up your smtp settings.
The concept of splitting the traditional message submission and message relay was proposed by the rfc.
Microsoft 365 or office 365 smtp relay does not require the use of a licensed microsoft 365 or office 365 mailbox to send emails.
Senders are not bound by the 30 messages per minute or 10 000 recipients per day limits.
Thus port 587 was assigned to message submission to make sure that the new policy and security requirements don t interfere with the traditional relay traffic over message relay port 25.
Mandatory requirements for smtp relay with office 365.
If you have applications which don t support these requirements but you would like to use the office 365 smtp and pop3 servers you can use stunnel to bridge the gap.
The smtp relay server that wants to relay mail to the office 365 mail infrastructure will.
Office 365 smtp settings.
Select outbound connections and in the tcp port box enter 587 and select ok.
Here s how you can set up office 365 smtp settings.
Set up exchange online as an smtp relay using windows server 2008 install internet information services iis in server manager select add roles.
This connector will receive smtp relay transactions from the application or device.
Enter the credentials of the office 365 user who you want to use to relay smtp mail.