138 lines
6.3 KiB
Markdown
138 lines
6.3 KiB
Markdown
# Email server setup script
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I wrote this script during the grueling process of installing and setting up
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an email server. It perfectly reproduces my successful steps to ensure the
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same setup time and time again, now with many improvements.
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I'm glad to say that dozens, hundreds of people have now used it and there is a
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sizeable network of people with email servers thanks to this script.
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I've linked this file on Github to a shorter, more memorable address on my
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website so you can get it on your machine with this short command:
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```sh
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curl -LO lukesmith.xyz/emailwiz.sh
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```
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When prompted by a dialog menu at the beginning, select "Internet Site", then
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give your full domain without any subdomain, i.e. `lukesmith.xyz`.
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## This script installs
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- **Postfix** to send and receive mail.
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- **Dovecot** to get mail to your email client (mutt, Thunderbird, etc.).
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- Config files that link the two above securely with native log-ins.
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- **Spamassassin** to prevent spam and allow you to make custom filters.
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- **OpenDKIM** to validate you so you can send to Gmail and other big sites.
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## This script does _not_
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- use a SQL database or anything like that.
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- set up a graphical interface for mail like Roundcube or Squirrel Mail. If you
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want that, you'll have to install it yourself. I just use
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[isync/msmtp/mutt-wizard](https://github.com/lukesmithxyz/mutt-wizard) to
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have an offline mirror of my email setup and I recommend the same. There are
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other ways of doing it though, like Thunderbird, etc.
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## Requirements
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1. A **Debian or Ubuntu server**. I've tested this on a
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[Vultr](https://www.vultr.com/?ref=8384069-6G) Debian server and one running
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Ubuntu and their setup works, but I suspect other VPS hosts will have
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similar/possibly identical default settings which will let you run this on
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them. Note that the affiliate link there to Vultr gives you a $100 credit
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for the first month to play around.
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2. **A Let's Encrypt SSL certificate for your site's `mail.` subdomain**.
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3. You need two little DNS records set on your domain registrar's site/DNS
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server: (1) an **MX record** pointing to your own main domain/IP and (2) a
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**CNAME record** for your `mail.` subdomain.
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4. **A Reverse DNS entry for your site.** Go to your VPS settings and add an
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entry for your IPv4 Reverse DNS that goes from your IP address to
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`<yourdomain.com>` (not mail subdomain). If you would like IPv6, you can do
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the same for that. This has been tested on Vultr, and all decent VPS hosts
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will have a section on their instance settings page to add a reverse DNS PTR
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entry.
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You can use the 'Test Email Server' or ':smtp' tool on
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[mxtoolbox](https://mxtoolbox.com/SuperTool.aspx) to test if you set up
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a reverse DNS correctly. This step is not required for everyone, but some
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big email services like Gmail will stop emails coming from mail servers
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with no/invalid rDNS lookups. This means your email will fail to even
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make it to the recipients spam folder; it will never make it to them.
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5. `apt purge` all your previous (failed) attempts to install and configure a
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mail server. Get rid of _all_ your system settings for Postfix, Dovecot,
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OpenDKIM and everything else. This script builds off of a fresh install.
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6. Some VPS providers block mail port numbers like 25, 993 or 587 by default.
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You may need to request these ports be opened to send mail successfully.
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Vultr and most other VPS providers will respond immediately and open the
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ports for you if you open a support ticket.
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## Post-install requirement!
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- After the script runs, you'll have to add additional DNS TXT records which
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are displayed at the end when the script is complete. They will help ensure
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your mail is validated and secure.
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## Making new users/mail accounts
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Let's say we want to add a user Billy and let him receive mail, run this:
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```
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useradd -m -G mail billy
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passwd billy
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```
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Any user added to the `mail` group will be able to receive mail. Suppose a user
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Cassie already exists and we want to let her receive mail too. Just run:
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```
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usermod -a -G mail cassie
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```
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A user's mail will appear in `~/Mail/`. If you want to see your mail while ssh'd
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in the server, you could just install mutt, add `set spoolfile="+Inbox"` to
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your `~/.muttrc` and use mutt to view and reply to mail. You'll probably want
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to log in remotely though:
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## Logging in from Thunderbird or mutt (and others) remotely
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Let's say you want to access your mail with Thunderbird or mutt or another
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email program. For my domain, the server information will be as follows:
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- SMTP server: `mail.lukesmith.xyz`
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- SMTP port: 587
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- IMAP server: `mail.lukesmith.xyz`
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- IMAP port: 993
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In previous versions of emailwiz, you also had to log on with *only* your
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username (i.e. `luke`) rather than your whole email address (i.e.
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`luke@lukesmith.xyz`), which caused some confusion. This is no longer the
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case.
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## Benefited from this?
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I am always glad to hear this script is still making life easy for people! If
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this script or documentation has saved you some frustration, you can donate to
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support me at [lukesmith.xyz/donate](https://lukesmith.xyz/donate.html).
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## Troubleshooting -- Can't send mail?
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- Always check `journalctl -xe` to see the specific problem.
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- Check with your VPS host and ask them to enable mail ports. Some providers
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disable them by default. It shouldn't take any time.
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- Go to [this site](https://appmaildev.com/en/dkim) to test your TXT records.
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If your DKIM, SPF or DMARC tests fail you probably copied in the TXT records
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incorrectly.
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- If everything looks good and you *can* send mail, but it still goes to Gmail
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or another big provider's spam directory, your domain (especially if it's a
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new one) might be on a public spam list. Check
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[this site](https://mxtoolbox.com/blacklists.aspx) to see if it is. Don't
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worry if you are: sometimes especially new domains are automatically assumed
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to be spam temporarily. If you are blacklisted by one of these, look into it
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and it will explain why and how to remove yourself.
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- Check your DNS settings using [this site](https://intodns.com/), it'll report
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any issues with your MX records
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- Ensure that port 25 is open on your server.
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[Vultr](https://www.vultr.com/docs/what-ports-are-blocked) for instance
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blocks this by default, you need to open a support ticket with them to open
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it. You can't send mail if 25 is blocked
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