SMTP Relay after Migrating to Exchange Online

Julian Benson 1 Reputation point
2022-04-12T07:59:27.05+00:00

Hi All

We have migrated all of our users to Exchange Online, currently running a Hybrid setup and was wondering what people are using to handle SMTP relay from internal apps to users. Currently i have a connector on our Exchange2013 server and it works really well, we add the sending server to the scope and away we go.

We expect to be turning these servers off in the near future and was wondering how others are dealing with it.

Any advice would be great.

Many thanks
Julian

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
4,305 questions
Microsoft Exchange Hybrid Management
Microsoft Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
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3 answers

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  1. Michel de Rooij 1,536 Reputation points MVP
    2022-04-12T09:34:08.9+00:00

    Many customers we onboarded leave a down-sized environment of current Exchange servers in Hybrid for recipient management and mail relay. Depending on your requirements, this may be the only supported solution as throwing 3rd party gateways in the mix for relaying results in application mail, MFC scan-to-mail etc. getting treated like regular mail, having it ending up in junk-mail or worse for internal recipients, causing you having to implement bypasses to prevent this behavior.

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  2. KyleXu-MSFT 26,226 Reputation points
    2022-04-13T02:09:59.03+00:00

    @Julian Benson

    You could follow this article to uninstall the Exchange on-premises if you don't need to use Exchange server, AAD Connect and ADFS. If you still use AAD Connect and ADFS, you need to keep at least one Exchange on-premises server (Scenario two in that article).

    About the relay function, you could use Exchange online to relay emails for your APP. Personally, I'd suggest you keep Exchange on-premises to relay mail, because it is easier to configure to relay than Exchange online.


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  3. Amit Singh 4,861 Reputation points
    2022-04-14T05:53:46.677+00:00

    Normally you need a licensed user to be able to send e-mails using SMTP with Office 365. Your applications also need support for TLS encryption. If your application doesn’t support TLS, or if you need to send emails from another address than the licensed user’s address, you need another solution. Luckily Office 365 can help you. The solution is to set up an inbound connector in Exchange Online Protection.

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