SMTP to Exchange Online - AdamFowlerIT.com
www.adamfowlerit.com › 2021 › 04Apr 22, 2021 · SMTP to Exchange Online. Posted on April 22, 2021. April 27, 2021. by Adam Fowler. SMTP is still needed by certain applications and devices, such as printers, which don’t support Modern Authentication and instead require legacy authentication to talk to a SMTP server. You are able to use Exchange Online as an SMTP server, but this can be tricky to set up if you’ve hardened your environment by requiring Multi-factor authentication through Security Defaults or Conditional Access.