Mail.

Message headers fields.

from            =       "From:" mailbox-list CRLF
sender          =       "Sender:" mailbox CRLF
reply-to        =       "Reply-To:" address-list CRLF

to              =       "To:" address-list CRLF
cc              =       "Cc:" address-list CRLF
bcc             =       "Bcc:" (address-list / [CFWS]) CRLF
newsgroups

http://tools.ietf.org/rfc//rfc2076.txt

Common Internet Message Headers, Informational

http://tools.ietf.org/rfc/rfc2822.txt

Internet Message Format, Standard Track

http://tools.ietf.org/rfc/rfc2821.txt

Simple Mail Transfer Protocol, Standard Track

Sending mail with ssmtp.

$ cat /etc/ssmtp/ssmtp.conf
Mailhub=smtp.gmail.com:587
FromLineOverride=YES
UseSTARTTLS=yes
AuthUser=gavenkoa
AuthPass=XXXXXX

Sending email via gmail in emacs.

; install starttls from here (no need for patch)
; http://josefsson.org/emacs-smtp-starttls.html

(setq send-mail-function 'smtpmail-send-it
   message-send-mail-function 'smtpmail-send-it
   smtpmail-starttls-credentials
   '(("smtp.gmail.com" 587 nil nil))
   smtpmail-auth-credentials
   (expand-file-name "~/.authinfo")
   smtpmail-default-smtp-server "smtp.gmail.com"
   smtpmail-smtp-server "smtp.gmail.com"
   smtpmail-smtp-service 587
   smtpmail-debug-info t
   starttls-extra-arguments nil
   smtpmail-warn-about-unknown-extensions t
   starttls-use-gnutls nil)

Update ~/..authinfo:

machine smtp.gmail.com login [your name]@gmail.com password [your password]

And finally download, unzip, make and install startttls:

http://josefsson.org/emacs-smtp-starttls.html

https://support.google.com/a/answer/33915

Configuring Your MX Records: Other domain hosts.

• http://justinsboringpage.blogspot.com/2009/02/sending-email-via-gmail-in-emacs.html
• http://obfuscatedcode.wordpress.com/2007/04/26/configuring-emacs-for-gmails-smtp

Mail etiquette.

Storage format for email.