# SimpleMailserver
A script to facilitate easy installation of a Postfix + Gmail relay for custom emails you can easily access from the gmail client or other clients supporting SMTPS and POP3

# Before installing
1. Some ports must be exposed to be able to host a mailserver, and to prevent abuse most registrars disable these ports by default. Contact support to have them opened:
   * 25: SMTP
   * 110: POP3
   * 143: IMAP
   * 465: SMTPS
   * 587: Submission
   * 993: Secure IMAP
   * 995: Secure POP3
2. Certain DNS records must be added, namely MX and AAAA. MX must contain the mail.domain.com domain and AAAA must contain the mail subdomain
![Example DNS records](images/aaaa.png)
2. Generate an app password at [https://myaccount.google.com/apppasswords](https://myaccount.google.com/apppasswords)
3. Select `Other (Custom name)` and enter a distinctive identifier, like `Mailserver mail.domain.com`
![Select app](images/select_app.png)
4. Select generate and keep this app password for installation. You will not be able to see it again so make sure to record it somewhere

![Generate app password](images/app_password.png)

# Installing
Run the following command to install
```shell
su - -c "bash <(curl -fsSL https://raw.githubusercontent.com/TheGreatRambler/SimpleMailserver/main/install.sh)"
```
The installation script will ask for some values:
* Domain name: Domain name used in the email, also required to configure SSL
* Mail subdomain: Subdomain where actual mailserver will be hosted, it is good practice to not put the mailserver at root
* Admin user: User where administrator mail like webmaster,postmaster etc will be sent
* Certbot email: Email where certbot, SSL, updates will be sent
* Gmail email: Email required to authenticate with the Gmail relay
* App password: Google app password under previous gmail that identifies this server to Google

# After installation
Your new mailserver is most useful when paired with a email client supporting SMTPS and POP3. Gmail has been tested to work but other clients likely work
1. Open `See all settings` on Gmail and navigate to `Accounts and import`
![Gmail account settings](images/settings.png)
2. Click `Add another email address` and fill out the form. Uncheck `Treat as an alias`
![Add email settings](images/add_email.png)
3. Configure using the desired user on the mailserver, like the admin user you entered earlier
![Enter mailserver](images/send_mail.png)
4. SSH into your mailserver. Check the mail using `runuser -l user -c 'mail'` with the user you entered. Enter the number of the most recent email from `Gmail Team` and search for `Confirmation code: XXXXXXXXX` in the body of the email. Copy that code and enter it into the dialog on the Gmail client. Exit `mail` by pressing q twice and pressing Enter.
5. Disable `Always reply from default address`
![Disable default address](images/default_address.png)
6. Click `Check mail from other accounts` and enter your custom email
![Enter email for check mail](images/check_mail.png)
7. Enable `Import emails from my other account (POP3)`
8. Fill out the form, making special care to use port 995

![Import email for check mail](images/import_email.png)
9. You can now send email under your custom email

![Send mail under custom email](images/send_message.png)

# Uninstalling
Run the following command to uninstall
```shell
su - -c "bash <(curl -fsSL https://raw.githubusercontent.com/TheGreatRambler/SimpleMailserver/main/uninstall.sh)"
```