Configuring MSMTP with gmail as a mail transfer agent

This is an easy-to-setup alternative to postfix or sendmail configuration. The instructions have been written for Debian but should be easy to adjust for other Linux distributions.

Instructions

1. Log in as root and issue the following command:
   apt install msmtp-mta bsd-mailx

2. Create the file .msmtprc inside home of asterisk user
   cat <<HERE > ~asterisk/.msmtprc
account default
host smtp.gmail.com
port 587
protocol smtp
auth on
from YOUR_GMAIL_ACCOUNT@gmail.com
user YOUR_GMAIL_ACCOUNT@gmail.com
password YOUR_PASSWORD
tls on
tls_starttls on
tls_certcheck off
HERE

3. Set correct permissions
   chown asterisk:asterisk ~asterisk/.msmtprc
chmod 600 ~asterisk/.msmtprc

4. Send a test email from CLI (under asterisk user)
   echo "test email" | mail -s test_email OTHER_EMAIL@SOME_PROVIDER.com

5. Test sending email from FreePBX