At this stage I move from basic email functionality into a fully validated mail system that can send and receive real-world email reliably.
The goal is:
Make sure my domain is verified, SMTP is authenticated, and email delivery works externally.
First I install Roundcube through Virtualmin.
This gives me a browser-based email interface so I can:
Log into mailboxes
Send test emails
Receive external emails
Verify IMAP is working correctly
At this stage Roundcube is purely for testing, not my main email client.
Inside Virtualmin, I create the first real mailbox user:
Username: (my chosen email user)
Password: (secure password set during creation)
Domain: webworkbench.co.uk
This becomes the first working email identity on the system.
Next I create an account with SMTP2GO to handle outgoing email delivery.
This improves:
Email deliverability
Spam reputation handling
Reliability from a home-hosted server
After creating the account, SMTP2GO requires domain verification before it will allow sending.py.
SMTP2GO generates 3 CNAME records that must be added into Namecheap DNS. These are used to prove ownership of the domain.
I add each CNAME record into Namecheap exactly as provided by SMTP2GO.
Once added:
SMTP2GO verifies the domain automatically
Outgoing mail is enabled for that domain
The system becomes trusted for sending email
Inside Virtualmin (Postfix configuration), I set SMTP relay:
i click on SMTP Authentication And Encryption option
Send outgoing mail via host: mail-eu.smtp2go.com:2525
Then Use SASL SMTP authentication set to Yes
On the Ubuntu server via SSH, I configure the SMTP authentication file:
sudo nano /etc/postfix/sasl_passwd
Add:
mail-eu.smtp2go.com:2525 SMTP2GO_USERNAME:SMTP2GO_PASSWORD
Then compile the map file:
sudo postmap /etc/postfix/sasl_passwd
Lock permissions:
sudo chmod 600 /etc/postfix/sasl_passwd
Restart Postfix:
sudo systemctl restart postfix
This ensures:
Postfix securely stores SMTP credentials
SMTP2GO handles all outbound email
Emails are properly authenticated
Domain is verified and trusted for sending
At this stage I also confirm:
MX record points to mail.webworkbench.co.uk
SMTP2GO CNAME verification is complete
Domain is fully authorised for sending email
Roundcube can send and receive messages
At the end of this stage: