I have Postfix 6.6. When I send a newsletter blast from our SMTP server, many of the recipient emails are not valid and so the spam gateway on the receiving mail server (different server) gets inundated with bounce messages.
I would like to mitigate this by configuring recipient verification, but I can't find a really informative guide on best practices and configuration steps. How do I set it up? Also, can I have it build a list of invalid recipients so make future lookups quicker, and to be able to use it to clean out the newsletter recipient list?
Also, can anyone with experience provide some of the disadvantages of doing this (aside from slowing down the mailing)?
BTW from what I understand, to enable basic recipient verification, I just add this to main.cf. Is this correct?
smtpd_recipient_restrictions = permit_mynetworks, reject_unauth_destination, reject_unverified_recipient