PostFix IP Authentication

Routing all outgoing mails via the outgoing smarthost (IP Authentication):

  1. Ensure the IP address is added as an Authorized Smarthost (without authentication)
  2. Ensure the Outgoing User has Enable Outgoing Connection Limits: ON
  3. Be sure that the correct limits are set matching your traffic volumes per Month, Week, Day, Hour and Minute
  4. Update your configuration
    1. Edit /etc/postfix/ and ensure it contains the following line:
    2. relayhost = SMARTHOST:587

  5. Restart PostFix

For information on smarthosts, see Outbound Filtering Hostnames