How do I set up ssmtp for use with Fastmail?

Question

There are plenty of guides on the web about setting up ssmtp for Gmail, but it's a bit different for different providers.

How should it be done for fastmail.com?

Answer 1

After installing ssmtp (sudo apt install ssmtp is all it takes), go to Password & Security settings, and create an App Password. It only needs permission for SMTP, nothing else.

Then, edit /etc/ssmtp/ssmtp.conf to resemble the following:

root=username@fastmail.com
AuthUser=username@fastmail.com
AuthPass=passwordGoesHere123
mailhub=smtp.fastmail.com:465
hostname=fastmail.com
FromLineOverride=NO
UseTLS=YES
UseSTARTTLS=NO

Replace username@fastmail.com with your actual Fastmail email address (which may not be @fastmail.com, but one of their other domain names) and use the App Password you created above for AuthPass.