Send mail to Gmail with SSMTP

Usually, you do not need to setup an email server under Linux desktop operating system. Most GUI email clients (such as Thunderbird) supports Gmail POP3 and IMAP configurations. But, how do you send mail via the standard or /usr/bin/mail user agents or a shell script? Programs such as sendmail / postfix / exim can be configured as a gmail smarthost but they are largely overkill for this use. 

You can use gmail as a smart host to send all messages from your Linux / UNIX desktop systems. You need to use a simple program called ssmtp. It accepts a mail stream on standard input with recipients specified on the command line and synchronously forwards the message to the mail transfer agent of a mailhub for the mailhub MTA to process. Failed messages are placed in dead.letter in the sender's home directory. 

Install ssmtp 

Type the following command under CentOS / RHEL / Red Hat / Fedora Linux: 

# rpm –Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm 
# yum install ssmtp 

Type the following command under Debian / Ubuntu Linux: 

# apt-get update && apt-get install ssmtp 

Configure gmail as a smarthost 

Open /etc/ssmtp/ssmtp.conf, enter: 

# vi /etc/ssmtp/ssmtp.conf 

Update file with the following settings: 

AuthUser=vivek@gmail.com 
AuthPass=Your-Gmail-Password 
FromLineOverride=YES 
mailhub=smtp.gmail.com:587 
UseSTARTTLS=YES 

Also, make sure you disable Sendmail: 

# service sendmail stop 
# chkconfig sendmail off 
# mkdir /root/.bakup 
# mv /usr/sbin/sendmail /root/.bakup 
# ln -s /usr/local/ssmtp/sbin/ssmtp /usr/sbin/sendmail 

Now, you can use mail / mailx command to send email messages. You can also write a shell script to backup your files and email to somewhere else (see below). You can test settings using following syntax: 

$ echo "This is a test" | mail -s "Test" vivek@nixcraft.co.in 

A note about sSMTP 

sSMTP works well for desktop systems, but it is not a replacement for Sendmail / Postfix / Exim / Qmail for email server environment. This software is perfect for a single user system.