(Postfix) set rate_delay for 2 sending domains to 1 receiving domain

Question

Currently I own 2 sender domains aaa.com and bbb.com. The restriction is that:

• Each domain can only send one email after another with a delay of 200 seconds.
• Each domain can only send 100 emails within 24 hours.

The following main.cf config is not applicable if I want to send emails from both domains to a single receiving domain at the same time, since all emails will be pending at one queue instead of two (per sending domains).

default_destination_rate_delay=200s
smtp_destination_concurrency_limit = 2
smtp_extra_recipient_limit = 100

Is there any solution for this kind of condition?

Answer 1

Find a solution by using Transport Map as below:

1. Edit the master.cf and add SMTP transports.

   aaa unix - - n - - smtp
   bbb unix - - n - - smtp
   

2. Create a transport file to map a domain with it’s transport name.

   @aaa.com     :aaa
   @bbb.com     :bbb
   

3. Add the policy to the main.cf

   default_destination_rate_delay=0
   default_destination_concurrency_limit = 2
   
   sender_dependent_default_transport_maps = hash:/etc/postfix/transport
   aaa_destination_rate_delay=200s
   bbb_destination_rate_delay=200s
   

4. Reload postfix to make changes

   postmap /etc/postfix/transport
   postfix reload