# Email server setup script

I wrote this script during the gruelling process of installing and setting up
an email server.  It perfectly reproduces my successful steps to ensure the
same setup time and time again.

I've linked this file on Github to a shorter, more memorable address on my
website so you can get it on your machine with this short command:

```sh
curl -LO lukesmith.xyz/emailwiz.sh
```

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

Read this readme and peruse the script's comments before running it.  Expect it
to fail and you have to do bug testing and you will be very happy when it
actually works perfectly.

## This script installs

- **Postfix** to send and receive mail.
- **Dovecot** to get mail to your email client (mutt, Thunderbird, etc).
- Config files that link the two above securely with native log-ins.
- **Spamassassin** to prevent spam and allow you to make custom filters.
- **OpenDKIM** to validate you so you can send to Gmail and other big sites.

## This script does _not_

- use a SQL database or anything like that.
- set up a graphical interface for mail like Roundcube or Squirrel Mail. If you
  want that, you'll have to install it yourself. I just use
  [isync/msmtp/mutt-wizard](https://github.com/lukesmithxyz/mutt-wizard) to
  have an offline mirror of my email setup and I recommend the same. There are
  other ways of doing it though, like Thunderbird, etc.

## Requirements

1. A **Debian or Ubuntu server**. I've tested this on a
   [Vultr](https://www.vultr.com/?ref=8384069-6G) Debian server and one running
   Ubuntu and their setup works, but I suspect other VPS hosts will have
   similar/possibly identical default settings which will let you run this on
   them. Note that the affiliate link there to Vultr gives you a $100 credit
   for the first month to play around.
2. **A Let's Encrypt SSL certificate for your site's `mail.` subdomain**.
   Create a nginx/apache site at `mail.<yourdomain.com>` and get a certificate
   for it with Let's Encrypt's [Certbot](https://certbot.eff.org/).
3. You need two little DNS records set on your domain registrar's site/DNS
   server: (1) an **MX record** pointing to your own main domain/IP and (2) a
   **CNAME record** for your `mail.` subdomain.
4. **A Reverse DNS entry for your site.** Go to your VPS settings and add an
   entry for your IPV4 Reverse DNS that goes from your IP address to
   `mail.<yourdomain.com>`. If you would like IPV6, you can do the same for
   that. This has been tested on Vultr, and all decent VPS hosts will have
   a section on their instance settings page to add a reverse DNS PTR entry.
   You can use the 'Test Email Server' or ':smtp' tool on
   [mxtoolbox](https://mxtoolbox.com/SuperTool.aspx) to test if you set up
   a reverse DNS correctly. This step is not required for everyone, but some
   big email services like gmail will stop emails coming from mail servers
   with no/invalid rDNS lookups. This means your email will fail to even
   make it to the receipients spam folder; it will never make it to them.
5. `apt purge` all your previous (failed) attempts to install and configure a
   mailserver. Get rid of _all_ your system settings for Postfix, Dovecot,
   OpenDKIM and everything else. This script builds off of a fresh install.
6. Some VPS providers block port 25 (used to send mail). You may need to
   request that this port be opened to send mail successfully. Although I have
   never had to do this on a Vultr VPS, others have had this issue so if you
   cannot send, contact your VPS provider.

## Post-install requirement!

- After the script runs, you'll have to add additional DNS TXT records which
  are displayed at the end when the script is complete. They will help ensure
  your mail is validated and secure.

## Making new users/mail accounts

Let's say we want to add a user Billy and let him receive mail, run this:

```
useradd -m -G mail billy
passwd billy
```

Any user added to the `mail` group will be able to receive mail. Suppose a user
Cassie already exists and we want to let her receive mail to. Just run:

```
usermod -a -G mail cassie
```

A user's mail will appear in `~/Mail/`. If you want to see your mail while ssh'd
in the server, you could just install mutt, add `set spoolfile="+Inbox"` to
your `~/.muttrc` and use mutt to view and reply to mail. You'll probably want
to log in remotely though:

## Logging in from Thunderbird or mutt (and others) remotely

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

- SMTP server: `mail.lukesmith.xyz`
- SMTP port: 587
- IMAP server: `mail.lukesmith.xyz`
- IMAP port: 993
- Username `luke` (i.e. *not* `luke@lukesmith.xyz`)

The last point is important. Many email systems use a full email address on
login. Since we just simply use local PAM logins, only the user's name is used
(this makes a difference if you're using my
[mutt-wizard](https://github.com/lukesmithxyz/mutt-wizard), etc.).

## Tweaking things

You're a big boy now if you have your own mail server!

## Benefited from this?

If this script or documentation has saved you some frustration, you can donate
to support me at [lukesmith.xyz/donate](https://lukesmith.xyz/donate.html).

## Troubleshooting -- Can't send mail?

- Always check `journalctl -xe` to see the specific problem.
- Go to [this site](https://appmaildev.com/en/dkim) 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](https://mxtoolbox.com/blacklists.aspx) to see if it is. Don't
  worry if you are: sometimes especially new domains are automatically assumed
  to be spam temporaily. 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](https://intodns.com/), it'll report any issues with your MX records
- Ensure that port 25 is open on your server. [Vultr](https://www.vultr.com/docs/what-ports-are-blocked) 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