msmtp
Today I took a look at mstmp:
“msmtp is an SMTP client that can be used as an “SMTP plugin” for Mutt and probably other MUAs (mail user agents).
It forwards mails to an SMTP server (for example at a free mail provider) which does the delivery.
To use this program, create a configuration file with your mail account(s) and tell your MUA to call msmtp instead of /usr/sbin/sendmail.”
msmtp is useful on hosts where doesn’t exist a working mailsetup or if you often have to change your setup [e.g. laptop]. msmtp provides a user-specific configuration instead of a host-based one.