Editing Email/Notification

== Set up SSL Certificate ==

You will need to set up a hostname (such as a subdomain, <code>server.yourdomain.com</code>) and an ssl certificate for that domain before you can send mail over SMTP.

https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-centos-7

Once you are done, link your certifiate to the postfix one:

<pre>sudo ln -s /etc/ssl/certs/ca-bundle.crt /etc/postfix/cacert.pem</pre>
== Set up Postfix ==

You will need an SMTP server to send mail. This doesn't handle recieving mail. Setting it up is similar to setting up a SMTP mail client on your phone or with Thunderbird.

Install the postfix SMTP Server (usually already installed on RHEL):

<pre>sudo yum install postfix mailx</pre>
=== Setup with Amazon SES ===

[https://docs.aws.amazon.com/ses/latest/DeveloperGuide/request-production-access.html?icmpid=docs_ses_console Amazon SES does put you in a sandbox by default to reduce spam.]

But you can verify the email addresses that are supposed to recieve it, which is great for just simple status reports from the server.

http://docs.aws.amazon.com/ses/latest/DeveloperGuide/postfix.html

==== Using SASL ====

You'll need to set up SASL support to use an SES account:

<pre>yum install cyrus-sasl-plain
service postfix restart</pre>
Now everything works fine for me:

<pre>[root@host postfix]# echo &quot;SES test&quot; | mail -s &quot;SES test `date +%s`&quot; -r &quot;me@domain.com&quot; recipient@domain.com</pre>
http://www.iredmail.org/forum/topic6582-iredmail-support-amazon-ec2-with-iredmail-and-amazon-ses.html

=== Setup With Gmail ===

Edit the postfix configuration file, and configure it with, for example, the Gmail SMTP servers:

<code>sudo nano /etc/postfix/main.cf</code>

<pre>relayhost = [smtp.gmail.com]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_CAfile = /etc/postfix/cacert.pem
smtp_use_tls = yes</pre>
Next, configure your email account, in this case Gmail:

<code>sudo nano /etc/postfix/sasl_passwd</code>

<pre>[smtp.gmail.com]:587    USERNAME@gmail.com:PASSWORD</pre>
Generate the hashed password db:

<pre>cd /etc/postfix
sudo postmap sasl_passwd</pre>
And now you're ready to send mail using Postfix. Here's an example command:

<pre> echo &quot;This is the message text.&quot; | mail -s &quot;the message subject&quot; recipient@gmail.com</pre>
* [https://easyengine.io/tutorials/linux/ubuntu-postfix-gmail-smtp/ Easyengine - Ubuntu Postfix Gmail SMTP]
* [http://unix.stackexchange.com/questions/116805/how-to-install-postfix-for-sending-mails-to-admin-only/118101#118101 StackExchange UNIX - How to install postfix for sending mails to admin only]

== Set up Systemd Notification ==

* [https://community.spiceworks.com/how_to/118108-avoiding-sysadmin-paranoia-with-the-right-it-monitoring-alerts Spiceworks - Avoid sysadmin paranoia with the right IT monitoring alerts]
* [http://northernlightlabs.se/systemd.status.mail.on.unit.failure Northern Lights Labs]