This article explains how to send email from the Raspberry Pi. It is a generic procedure and also works on other Debian distributions. This is not for receiving mail, only for sending it. (Receiving email on the Pi is a much more involved process, requiring your Pi to perform the role of a full mail server).
The ability to send mail across the Internet is useful. It enables scripts and applications to send you email about system events or the sending data such as pictures from a webcam.
This article was updated in December 2019 and has been successfully tested on Raspbian Stretch, Jessie and Buster/Debian 10.
These days, service providers like British Telecom have tightened up their requirements on email delivery. Most ISPs now accept email only from servers that can authenticate through SMTP. Sendmail has authentication built in, allowing administrators to use an “authinfo” file, for example. The server then authenticates every time it sends mail out to the ISP.
That’s great for reducing spam. But it can have a side-effect of killing local mail on the server. Here is an recent example from Debian Squeeze. The authentication features that allowed this server to successfully send mail through the ISP were preventing local mail from working: Continue reading →