SSMTP is used to send outgoing emails without a mail server. It hands off all mail delivery to a third party client.

Sample configuration using all options

# User to get all emails for userids less than 1000
# Third-party SMTP server, port
# The source domain, what domain the email comes "from"
# FQDN Hostname, if unset, checks the system
# Email address that it is from
# Use TLS to talk to the SMTP server.  Default is no
# Specifies whether ssmtp does a EHLO/STARTTLS before starting SSL negotiation.
# The user name to use for SMTP AUTH.  The default is blank, in which case SMTP AUTH is not used.
# The password to use for SMTP AUTH.
# The authorization method to use.  If unset, plain text is used. May also be set to “cram-md5”.