Alllow sending through relayhost without authentication

Hi,

When sending email, sending domain matched relay_host in mail_domain database, postfix should send email through relay even the relay have no authentication.

main.conf

Code:

smtpd_relay_restrictions =     permit_mynetworks,permit_sasl_authenticated, check_sender_relay_auth, reject_unauth_destination
check_sender_relay_auth =     permit_auth_destination, permit_sasl_authenticated, permit

mysql-virtual_sender-relayauth.cf

Code:

user = user
password = password
dbname = dbname
hosts = 127.0.0.1
query = SELECT CONCAT(relay_user,':',relay_pass) as credential
  FROM mail_domain
  WHERE domain = '%d'
  AND active = 'y'
  AND relay_host != ''
  AND concat(relay_user,relay_pass) != ''
  AND server_id = 1

systemctl restart postfix

This is when I have to use smtp-relay.gmail.com but always getting sasl auth error.
Only do this if there is only you using the server, if there are others using it, they may add the same relayhost for their domain and bypass the authentication, and may affect your google account.

Thanks

 

This is dangerous - I wouldn't recommend anyone do this in todays time. Authentication should be bare minimum