Update 11/13/2023: We added new information on how to know when this change is released to your organization.
Today, we are announcing an update to our requirements for SMTP relay through Exchange ...
Updated Feb 22, 2024
Version 19.0
Blog Post
Hi Carolyn_Liu The_Exchange_Team
Our setup is similar to : https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/use-connectors-to-configure-mail-flow/integrate-office-365-with-an-email-add-on-service?redirectedfrom=MSDN where multiple exchange online tenants to our SMTP server and SMTP server to email back to ExchangeOnline for relay. This achieved using outbound and inbound connector.
But we do not support a unique certificate for each tenant, instead each tenant uses the same ip address of the SMTP server.
In the below comment it was mentioned that it is not a good idea to use same ip addresses across different exchange online tenants' inbound connectors.
I would like to understand if Microsoft has plans to restrict this type of configuration ? If so when is it planned?
We are trying to shift to unique certificate per Exchange online tenant approach and above information will help us to plan it accordingly.