For your Sipmon to be able to send notification emails, you need to configure a local smtp server. If your operating system is RHEL, CentOS or Oracle Linux, Postfix is already installed.

This page gives you an example of a possible configuration. Refer to the official Postfix documentation for more information.

Notifications commands are executed by the poller that monitors the resource: you need to configure the mail relay on all pollers.

We recommend that you use a dedicated email account to send notifications.

Step 1: Configuring Postfix

1. In your server's terminal, enter the following command:

   yum -y install mailx cyrus-sasl-plain

2. Restart Postfix:

   systemctl restart postfix

3. Configure Postfix to run at startup:

   systemctl enable postfix

4. Edit the following file:

   vi /etc/postfix/main.cf

5. Add the following information:

   myhostname = hostname
   relayhost = [smtp.isp.com]:port
   smtp_use_tls = yes
   smtp_sasl_auth_enable = yes
   smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
   smtp_tls_CAfile = /etc/ssl/certs/ca-bundle.crt
   smtp_sasl_security_options = noanonymous
   smtp_sasl_tls_security_options = noanonymous

   • myhostname is the hostname of the Sipmon server.
   • relayhost is the email server for the account that will send notifications.

   In the following example, Sipmon will use a Gmail account to send notifications:

   myhostname = Sipmon-central
   relayhost = [smtp.gmail.com]:587
   smtp_use_tls = yes
   smtp_sasl_auth_enable = yes
   smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
   smtp_tls_CAfile = /etc/ssl/certs/ca-bundle.crt
   smtp_sasl_security_options = noanonymous
   smtp_sasl_tls_security_options = noanonymous

Step 2: Configuring the credentials of the account that will send emails

1. Create a /etc/postfix/sasl_passwd file:

   touch /etc/postfix/sasl_passwd

2. Add the following line (replace username:password by the credentials of the account that will send the notification emails):

   [smtp.isp.com]:port username:password

   Example:

   [smtp.gmail.com]:587 username@gmail.com:XXXXXXXX

3. Save the file.

4. In the terminal, enter the following command:

   postmap /etc/postfix/sasl_passwd

5. For security reasons, change the permissions on the file:

   chown root:postfix /etc/postfix/sasl_passwd*
   chmod 640 /etc/postfix/sasl_passwd*

6. Reload Postfix so that chenges are taken into account:

   systemctl reload postfix

Testing and troubleshooting email configuration

• To send a test email, enter the following command:

  echo "Test" | mail -s "Test" user@isp.com

  Replace user@isp.com by a real email address: the recipient should receive the test email.

• If the user hasn't received the message, check the following log file:

  tail -f /var/log/maillog

• To check that your Postfix service is running, enter:

  systemctl status postfix

  The results should look like this:

  

Gmail configuration

If you want to send emails through a Gmail account, you will need to turn on the Allow less secure apps option on this account. See Less secure apps & your Google Account.