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


You are thinking about this entirely the wrong way. Those bounce messages are a valuable resource to you; they are the only way for you to clean out those non-working addresses from your mailinglist so that you can stop sending messages to addresses that don't exist.

When configuring your mailing list, you should set the envelope sender address to an address that does not go to a human - instead, it should go to a script that will remove those addresses from the mailing list.

If you keep sending mails to addresses that are known to not exist, you risk having your servers blacklisted as originators of spam. DO NOT DO THIS!

Before you send out another mail, you really need to look at some best practices for sending bulk emails.

As for your configuration question - the config you posted is for smtpd, which is for incoming mail. It does not affect outgoing mail.

  • Well we are in the process of getting our email lists cleaned professionally but waiting on the client's approval. In the meantime, how would I enable recipient verification on outgoing mail? – blizz Jun 5 '13 at 13:22
  • You can't. That's not how it works. – Jenny D Jun 5 '13 at 13:28
  • Alright, thanks for the suggestions everyone. I will look into setting up a powershell script to parse bounce messages. – blizz Jun 5 '13 at 13:57

Firstly, I agree with everything Jenny D said.

I strongly recommend that you get yourself some mailing list software that handles all this stuff for you, or use a service provider of some sort for it. You don't want to go re-inventing the wheel on this one. It's a big area and you're just scratching the surface.

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