In a previous post I wrote about the problems I had encountered while trying to configure my Ubuntu Server to send emails from the command line (actually from a script but it amounts to the same thing). I overcame the problem in the short term by using curl to send messages via Twitter but I really wanted to work out how to end emails instead. Well after a bit more research and some testing I have cracked it :-)
What I didn't understand was that I needed two components to be able to send an email in this way, a Mail Transfer Agent (MTA) and an email client. For my solution I have used Nullmailer as my MTA and Mutt as my Client.
Nullmailer is not a full blown MTA like Postfix but then I didn't really need something that heavyweight for my purposes. Nullmailer is a 'minimal mail relay' - it doesn't handle local mail delivery or download message from other servers, it just passes email from the local machine to a mail server for delivery.
Mutt is a small but powerful, text-based email client which can send email from the command line but also has a GUI (of sorts). I was only interested in the command line interface for this little project.
Both of these packages are available from the standard Ubuntu repositories so installation is just an apt-get away:
sudo apt-get install nullmailer mutt
During the installation of Nullmailer you will be prompted for a Host Name and a Remote Server.
The host name is just the domain part of your email address ; e.g. onthefencedevelopment.com
The remote server configuration is described on screen but consists of three sections (on one line); address protocol option
The configuration for my server looked like this (should be all on a single line):
mail.onthefencedevelopment.com smtp --auth-login --user=USERNAME --pass=PASSWORD
In contrast Mutt just installed itself without any help from me - which is how I like it.
Ok, so I have my MTA and my Client - how do I send an email.?
Well it's actually as easy as this (entered on a single line):
echo "Hello World, This is a test" | mutt -s "Testing Testing 1 2 3" firstname.lastname@example.org
This will send an email to email@example.com with the subject "Testing Testing 1 2 3" and the message of "Hello World, This is a test". It doesn't get much easier than that does it?
So now I can replace my Tweets with EMails - which can (thanks to Mutt) contain more than 140 characters and file attachments, thus making it useful for sending logs and detailed diagnostic information.
STOP THE PRESS...!!
Well it looks like I'm not quite done here as looking at my OpenDNS logs I see tens of thousands of requests to my mail server - what is all that about, i only have a couple of emails from my server!
Looks like something else is creating and queuing messages in addition to my call to Mutt.
[Update] Well it looks like it was either my twitter script or the call to logger that was causing this problem. Not needing the Twitter anymore and deciding that I didn't need to log everything I pulled these lines out and the spurious emails were a thing of the past.