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Email authentication
MTA-STS
A comprehensive collection of questions and answers about MTA-STS email authentication from email marketers, experts and technical documentation.
What is the 'mx' field in an MTA-STS policy used for?
Does MTA-STS apply to inbound or outbound mail?
Does MTA-STS work with any TLS certificate?
What HTTP status code should an MTA-STS policy file return on success?
What are the three possible 'mode' values in an MTA-STS policy?
Does MTA-STS require a specific root certificate authority?
What is the 'enforce' mode in MTA-STS?
Does MTA-STS use SMTP or HTTPS for policy retrieval?
What is the 'testing' mode in MTA-STS?
What is the 'none' mode in MTA-STS?
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