SSMTP is a program which delivers email from a local computer to a configured mailhost (mailhub). It is not a mail server (like feature-rich mail server sendmail) and does not receive mail, expand aliases or manage a queue. One of its primary uses is for forwarding automated email (like system alerts) off your machine and to an external email address.
ssmtp is unmaintained. Consider using something like msmtp instead.
Install the package .
Forward to a Gmail mail server
To configure SSMTP, you will have to edit its configuration file (
/etc/ssmtp/ssmtp.conf) and enter your account settings.
If your Gmail account is secured with two-factor authentication, you need to generate a unique App Password to use in
ssmtp.conf. You can do so on your App Passwords page. Use the generated 16-character password in the
AuthPass line. Spaces in the password can be omitted.
# The user that gets all the mails (UID < 1000, usually the admin) email@example.com # The mail server (where the mail is sent to), both port 465 or 587 should be acceptable # See also https://support.google.com/mail/answer/78799 mailhub=smtp.gmail.com:587 # The address where the mail appears to come from for user authentication. rewriteDomain=gmail.com # The full hostname. Must be correctly formed, fully qualified domain name or GMail will reject connection. hostname=yourlocalhost.yourlocaldomain.tld # Use SSL/TLS before starting negotiation UseTLS=Yes UseSTARTTLS=Yes # Username/Password AuthUser=username AuthPass=password AuthMethod=LOGIN # Email 'From header's can override the default domain? FromLineOverride=yes
Create aliases for local usernames (optional)
To test whether the Gmail server will properly forward your email:
$ echo test | mail -v -s "testing ssmtp setup" firstname.lastname@example.org
Change the 'From' text by editing
/etc/passwd to receive mail from 'root at myhost' instead of just 'root'.
# chfn -f 'root at myhost' root # chfn -f 'mainuser at myhost' mainuser
$ grep myhostname /etc/passwd
Because your email password is stored as cleartext in
/etc/ssmtp/ssmtp.conf, it is important to secure the file.
Securing ssmtp.conf will ensure that:
- if any users have unprivileged access to your system, they cannot read the file and see your email password, while still letting them send out email
- if your user account is ever compromised, the hacker cannot read the
ssmtp.conffile, and therefore your email password, unless he gains access to the root account as well
ssmtp.conf, do this:
# groupadd ssmtp
Set ssmtp.conf group owner to the new
# chown :ssmtp /etc/ssmtp/ssmtp.conf
Set the group owner of the ssmtp binary to the new
# chown :ssmtp /usr/bin/ssmtp
Make sure only root, and the
ssmtp group can access
# chmod 640 /etc/ssmtp/ssmtp.conf
Set the SGID bit on the ssmtp binary.
# chmod g+s /usr/bin/ssmtp
Finally add a pacman hook to always set the file permissions on
/usr/bin/ssmtp after the package has been upgraded:
#!/bin/bash chown :ssmtp /usr/bin/ssmtp chmod g+s /usr/bin/ssmtp
Make the file executable:
# chmod u+x /root/bin/ssmtp-set-permissions
Now add the pacman hook:
[Trigger] Operation = Install Operation = Upgrade Type = Package Target = ssmtp [Action] Description = Set ssmtp permissions for security When = PostTransaction Exec = /root/bin/set-ssmtp-permissions
Now, all the regular users can still send email using the terminal, but none can read the
To send email from the terminal, do:
$ echo "this is the body" | mail -s "Subject" email@example.com
or interactively as:
$ mail firstname.lastname@example.org
An alternate method for sending emails is to create a text file and send it with ssmtp or mail
To:email@example.com From:firstname.lastname@example.org Subject: Test This is a test mail.
$ mail email@example.com < test-mail.txt
Alternatively, you can attach using uuencode:
$ uuencode file.txt file.txt | mail firstname.lastname@example.org