Customer has hybrid exchange server running on Azure. They need to move subscription to CSP but understand that port 25 will be blocked.

Question

move to CSP. Customer has hybrid exchange server running on Azure. They need to move subscription to CSP but understand that port 25 will be blocked. They have a need to keep one mailbox running on the hybrid server as it is a moderated mailbox. Is there a way to change the connectors to communicate over port 587? when they have tried the email flow stopped.

Answer 1

@Isabel Fernandes

If you have a smart host (may be need to buy from third-party) to forward email to other organization, you could create a Send Connector which doesn't use 25 port to send emails for Exchange on-premises. For more detailed information, you could have a look about this article: New-SendConnector

If your Exchange on-premises in Azure cannot use 25 port, why not send emails from Exchange online mailbox directly?

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Answer 2

The hybrid exchange server is hosted in an Azure VM though. There is no on-premises infrastructure.
the send connector between hybrid server and O365 needs to use port 25, isn't that correct? is there a way to change it to 587?