SMTP relay o365 (Send email from application or device to o365 in hybrid mode)



can i send email to o365 with direct send method in hybrid configuration ?


the mail its send to local user in domaine o365 but not send to external user 

I have an exchange server 2013 hybrid with o365 and the MX is on o365 ( the traffic mail work correctly ) 

i put the  public @ip adresse in receive connector .. the mail its send to local user in domaine o365 but not send to external user from application when i want send notification to externe user 

we want to modify all notification in exchange to o365 , after that we remove the exchange 



i read this article and i configure the 3rd option

thank you for help 

4 Replies



Hi, in an Exchange Hybrid environment, the preferred method to SMTP relay is through the Exchange Hybrid server itself. 


I note that you are planning to remove your Exchange server?  If you do this, and continue synchronising your AD to Azure AD, then you will be putting yourself in a position where you are not supported by Microsoft.


So I would recommend keeping at least one Exchange Server to act as Management Server and SMTP relay.

best response confirmed by Kais_mbarki (Contributor)
Although I do agree with you Peter on leaving the last Exchange server in place, the option stated by @Kais_mbarki should work.
Requirements are creating a connector in EXO from his WAN IP (or option e-mail server of your org in the EXO ECP) to Office 365 and adding a whitelist entry for the IP in EXO as well.
If you then specify your Office 365 "MX record" so in the app as the mail server with port set to 25 and SSL to ON it should work.
I have several clients who are using Office 365 as a relay server this way.
By the way, I wouldn't suggest using the authentication method anymore because basic auth support will be discontinued in the future.



I do agree it should work.  Have done so many times this way myself.  I have found this method can be inconsistent and unreliable at times however.  But yes, it does work.

Thank you,
it worked following the change from organization type connectors to mail server type