I want to confirm to SPF and DKIM, this requires me to send email using the IP written in the DNS record of the domain
I have two domains example1.com and example2.com with two IPs 184.108.40.206 and 220.127.116.11 respectively.
How can I configure postfix to always use IP 18.104.22.168 when the send from address is firstname.lastname@example.org and the same to be true for the other domain.
When connecting to the SMTP transport I am using localhost, I know I can configure two postfix instances for each IP and then just connect to the right IP when sending depending on the domain, I would like to see if this can be avoided.
How can this be done?