See MSMTP Home Page.
;; Select the correct smtp server based on the from address.
(defun msmtp-account (&optional def)
(let* ((from
(save-restriction
(message-narrow-to-headers)
(message-fetch-field "From")))
(account (if from (catch 'match
(dolist (element msmtp-name-list)
;; (message (format "smpt chosen is %s" element))
(when (string-match (format ".*%s.*" element) from)
(throw 'match element)))) nil)))
(if account account (if def def "default"))))
(defun msmtp-change-smtp ()
(setq sendmail-program "/usr/bin/msmtp")
(setq smtpmail-starttls-credentials '(("smtp.googlemail.com" 587 nil nil)))
(setq smtpmail-smtp-server "smtp.googlemail.com")
(setq message-sendmail-envelope-from 'header)
(if (message-mail-p)
(setq message-sendmail-extra-arguments (list "-a" (msmtp-account "default")))))
(add-hook 'message-send-hook 'msmtp-change-smtp)
(setq message-required-news-headers
(remove' Message-ID message-required-news-headers))
