Meaning of "Sender must be valid"=dword:00000000

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Meaning of "Sender must be valid"=dword:00000000

Post by fbmaxwell » Sun Apr 30, 2017 11:06 am

I can't find any documentation for this SMTP registry key:

"Sender must be valid"=dword:00000000

The name sounds like something I'd want (who wants email from invalid senders?), but I don't know what it checks for validity and what values are valid for the key.

I know that there's a separate check for valid domains with mail servers, so I don't know if this is the format of the sender email address, whether the email address exists (with an RCPT TO: back-connection test), or something else.

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Re: Meaning of "Sender must be valid"=dword:00000000

Post by MailEnable-Ian » Tue May 02, 2017 11:13 pm


The "Sender must be Valid" registry key is the option for enabling/disabling "Authenticated senders must use address from their postoffice" located under the SMTP "Security" tab. When this is set to "1" (Enabled) it will force any authenticated user to send from an address that is mapped to their account/postoffice.

Ian Margarone
MailEnable Support

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