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

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
3. Generate an app password at https://myaccount.google.com/apppasswords
4. Select Other (Custom name) and enter a distinctive identifier, like Mailserver mail.domain.com
5. 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

Run the following command to install

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

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
2. Click Add another email address and fill out the form. Uncheck Treat as an alias
3. Configure using the desired user on the mailserver, like the admin user you entered earlier
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
6. Click Check mail from other accounts and enter your custom email
7. Enable Import emails from my other account (POP3)
8. Fill out the form, making special care to use port 995

9. You can now send email under your custom email

1. Create SPF record as a TXT record, replacing the IP with your own

Value: v=spf1 ip4:127.0.0.1 ~all 

2. Create DMARC record as a TXT record, replacing the email with the email you want to recieve periodic DMARC reports

Hostname: _dmarc
Value: v=DMARC1; p=reject; rua=mailto:[email protected]; adkim=s; aspf=s; sp=reject

3. Create default BIMI record, replacing the URL to an image to your desired profile picture

Hostname: default._bimi
Value: v=BIMI1; l=https://example.com/bimi/logo.svg;a=self;

The profile picture must be SVG Tiny 1.2, which is a slightly different version of SVG. When you generate your SVG ensure the following attributes are set:

<svg
   version="1.2"
   baseProfile="tiny-ps"
   ...
   xmlns="http://www.w3.org/2000/svg">

Line endings must also be LF only (Windows uses CR LF by default) 4. Support for Gmail and Outlook require a VMC. Because it is 1500$ a year I can't provide a guide on it

1. Navigate to Google Account -> Personal info -> Contact Info -> Alternate emails and add your custom email there
2. Set the profile picture of that Google account to the desired picture

Run the following command to uninstall

su - -c "bash <(curl -fsSL https://raw.githubusercontent.com/TheGreatRambler/SimpleMailserver/main/uninstall.sh)"