Our SharePoint 2016 farm have 2 WFE, 2 APP, and 2 Search servers.

In the outgoing server settings, we point to our company SMTP (smtp.company.com).

In order to allow the SMTP relay for SharePoint's email, we need to apply firewall open. Although we can simply apply open for all 6 servers but I want to understand the traffic logic.

Should I expect all email will be started from WFE? Or it will be started from other server depends on server role?

2 Answers 2


As per my knowledge, WFE servers are responsible to send emails. Traffic handling (incoming and outgoing emails) is based on the Load Balancer and how the load is shared.


Email sends from servers where Microsoft SharePoint Foundation Web Application service is enabled. These servers should be WFE servers.

On our firewall only WFE servers allowed to send emails. For a test I tried to enable Microsoft SharePoint Foundation Web Application service on APP server and email wasn't sent.

  • I also get this knowledge from other source. However I cannot find any official doc or sharing from MVP.
    – Mark L
    Sep 19, 2019 at 6:04

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