Mail send via Relay host on Ubuntu Server
From WikiMLT
Setup Gmail as Relay host
Edit /etc/postfix/main.cf as follow.
sudo nano /etc/postfix/main.cf
#Apply
# This tells Postfix to hand off all messages to Gmail, and never do direct delivery.
relayhost = [smtp.gmail.com]:587
# This enables TLS (SMTPS) certificate verification, because Gmail has a valid one.
smtp_tls_security_level = verify
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
smtp_tls_session_cache_database = btree:/var/run/smtp_tls_session_cache
# This tells Postfix to provide the username/password when Gmail asks for one.
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
In /etc/postfix/sasl_passwd, add your Gmail username and application password (see the references below).
sudo nano /etc/postfix/sasl_passwd
#Apply
[smtp.gmail.com]:587 user-name@gmail.com:app-password
# Note you must setup App Password at https://myaccount.google.com/u/0/apppasswords
Compile the sasl_passwd file into a database and reload Postfix's main configuration.
sudo postmap /etc/postfix/sasl_passwd && sudo postfix reload
Test the configuration
echo "Tes is sent at: $(date)" | mail -s "Test subject" email@example.com
References and Notes
- Super User: How do I change postfix port from 25 to 587?
- Google Support: Sign in with App Passwords
- Gmail as SMTP Client (refs)
- Note: With this configuration, all mail must be sent using your Gmail address as "From", unless you have setup your Gmail (
Settings>Accounts and Import>) to "Send mail as" some other, then you cold use these email addresses. - See also: Ubuntu Server at DO # Mail_Send
