Exchange 2019 multi-tenant - mail flow - sending between tenants?

Copper Contributor

We have built a Exchange 2019 Multi-tenant server using the recommendations made in the document below and step-by-steps provided for Exchange 2019:


When sending e-mails between clients (tenants) who are hosted on the multi-tenant Exchange, mail is sent directly within Exchange as Exchange knows who everyone is.

We need Exchange to always send out mail via SMTP if the receiving domain is not their own
Eg: to – can be delivered internally by Exchange
but to – must be sent via SMTP – out to the internet and back again.


Is there a way to force SMTP outgoing e-mail to use MX records and not route internally?


The problem here is :
A) When setting up or migrating a new client, once the domain for that client is in Exchange and the user is set up, any mail we try to send to that client will be delivered Internally even though we really haven’t activated the client.




2 Replies

Hi , 


I have same problem here , did you solve the issue ? @ssmitty 




@ssmitty Please follow the steps in the official document. You may also refer to the Official document for deployment scenarios and accordingly apply the appropriate solution.