is @code{sendmail-send-it}, which delivers mail using the Sendmail
installation on the local host. To send mail through a SMTP server,
set it to @code{smtpmail-send-it} and set up the Emacs SMTP library
is @code{sendmail-send-it}, which delivers mail using the Sendmail
installation on the local host. To send mail through a SMTP server,
set it to @code{smtpmail-send-it} and set up the Emacs SMTP library