After setting up a series of complex platforms, I needed a means of getting alerts to me should any of these fail. While a centralised platform such as Slack is normally better for operations teams, it doesn’t really work out that way for a home network and email will do the trick, but since I want things to be centralised I’ll need a mail server first.
Since there’s no need to receive any mail we can just use a send-only mail spooler and I’ll be using my favorite spooler, Exim. A lightweight and highly flexible spooler for email, one of the oldest and most stable options for this use.
I’m only going to be configuring for internal, unauthenticated SMTP transport over TCP port 25. This would never usually be an acceptable configuration for true production use, however I’m only allowing this movement of traffic within my own network for error notifications. There are also other mitigating steps protecting this system from attackers shown below.
Operating System: Ubuntu 16.04
Required Applications: exim-daemon-light, mailutils
Install the Pre-Requisite Software
sudo apt-get update sudo apt-get install exim-daemon-light mailutils
Configure the Exim Spooler
Once installed, I’ll configure the Spooler:
This will present a text based configuration wizard for Exim:
I now have a working spooler, and it can be tested by either setting up a remote system, or from the localhost by running:
echo "This is the body of the message" | mail -s FakeSubject firstname.lastname@example.org
Simple as that 🙂