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SMTP Relay in Exchange Online

shocko 100 Reputation points
2024-09-22T14:50:37.96+00:00

Currently we run Exchnage 2019 hybrid. We have not moved our MX records to Exchange Online yet for specific reasons so all mail flow is through Exchange 2019. That said, nearly all user/shared mailboxes have been migrated to Exchange Online. We also have many devices using SMTP relay through Exchange 2019 on-prem (printers etc.) to send mails mainly internally but also some externally (UPS devices for example). Most of these devices do not support authentication so we have setup a mail connector that uses an IP whitelist on Exchange 2019 to handle this. If we get rid of the hybrid and move to Exchange Online what options would we have for this type of unauthenticated relay?

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.
4,542 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.
2,112 questions

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  1. Andy David - MVP 148.4K Reputation points MVP
    2024-09-22T16:24:36.8766667+00:00

    Here are your options:

    https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365

    3 probably fits.

    If you need to do this, I recommend keeping an Exch Server on-prem or an Exchange Edge Role server to route mail .

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