= Alerting and Notification on Icinga2 =

Like in LibreNMS, we can setup multiple alerting mechanisms in Icinga2, and since Icinga Stack is a more advanced software, any type of custom notification  system can be associated. In this tutorial, we will only focus on setting up email, slack and telegram alerting systems.

== Email Setup ==

By default, Icinga supports email notifications, but we need to configure an email server on the Icinga node as it will be using the Linux mail utilities for sending the mails.

During the initial installation, we installed `postfix`. Now we need to add google credentials to it so that your server can send mails using Google.

Edit `/etc/postfix/main.cf`

Change following. ( DO NOT copy paste these in to the end of the file )

{{{

# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_security_level=may

smtp_tls_CApath=/etc/ssl/certs
smtp_tls_security_level=may
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

relayhost = [smtp.gmail.com]:587
smtp_use_tls = yes
smtp_sasl_auth_enable = yes
smtp_sasl_security_options =
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt

}}}

Create `/etc/postfix/sasl_passwd` with your Google username and password

{{{
[smtp.gmail.com]:587 thilinapathiedulk@gmail.com:MyPassw)<#
}}}

where `MyPassw)<#` would be my password for google. On google you have to make sure, Less Secure Apps are enabled.

now restart postfix

`systemctl restart postfix`

Test mail transport by `mail -s "Hello World" youremail@yourdomain.tld`