This script automates the grueling process of installing and setting up an email server. It perfectly reproduces my successful steps to ensure the same setup time and time again, now with many improvements.

When prompted by a dialog menu at the beginning, select "Internet Site", then give your full domain without any subdomain, i.e. example.com.

Let's say you want to access your mail with Thunderbird or mutt or another email program. The server information will be as follows:

• SMTP server: mail.example.com
• SMTP port: 587
• IMAP server: mail.example.com
• IMAP port: 993

• Always check journalctl -xe to see the specific problem.
• Go to this site to test your TXT records. If your DKIM, SPF or DMARC tests fail you probably copied in the TXT records incorrectly.
• If everything looks good and you can send mail, but it still goes to Gmail or another big provider's spam directory, your domain (especially if it's a new one) might be on a public spam list. Check this site to see if it is. Don't worry if you are: sometimes especially new domains are automatically assumed to be spam temporarily. If you are blacklisted by one of these, look into it and it will explain why and how to remove yourself.
• Check your DNS settings using this site, it'll report any issues with your MX records
• Ensure that port 25 is open on your server. Vultr for instance blocks this by default, you need to open a support ticket with them to open it. You can't send mail if 25 is blocked