{"draft":"draft-ietf-uta-smtp-require-tls-09","doc_id":"RFC8689","title":"SMTP Require TLS Option","authors":["J. Fenton"],"format":["HTML","TEXT","PDF","XML"],"page_count":"16","pub_status":"PROPOSED STANDARD","status":"PROPOSED STANDARD","source":"Using TLS in Applications","abstract":"The SMTP STARTTLS option, used in negotiating transport-level\r\nencryption of SMTP connections, is not as useful from a security\r\nstandpoint as it might be because of its opportunistic nature;\r\nmessage delivery is, by default, prioritized over security. This\r\ndocument describes an SMTP service extension, REQUIRETLS, and a\r\nmessage header field, TLS-Required. If the REQUIRETLS option or\r\nTLS-Required message header field is used when sending a message, it\r\nasserts a request on the part of the message sender to override the\r\ndefault negotiation of TLS, either by requiring that TLS be\r\nnegotiated when the message is relayed or by requesting that\r\nrecipient-side policy mechanisms such as MTA-STS and DNS-Based\r\nAuthentication of Named Entities (DANE) be ignored when relaying a\r\nmessage for which security is unimportant.","pub_date":"November 2019","keywords":["SMTP"],"obsoletes":[],"obsoleted_by":[],"updates":[],"updated_by":[],"see_also":[],"doi":"10.17487\/RFC8689","errata_url":"https:\/\/www.rfc-editor.org\/errata\/rfc8689"}