[lug] Making Postfix Play Nice (I'm not spam, really!)

[David L. Anselmi]

Ben Luey wrote:
> When sending out e-mails to our mailing list, I'm having a problem with
> some sites thinking I'm sending spam and blocking my mail server. I'm
> running postfix and the problem is that many of our subscribers have the
> same domain / mail server (say example.net). Postfix starts sending the
> users' mail. After ~10 emails in a row to example.net, example's smtp
> says "451 4.3.2 Please try again later (in reply to MAIL FROM command))"
> as a spam blocking protection.

Is it giving the message once, with many RCPT TOs?  That seems like the sensible thing.  If it isn't 
you might try setting it to.

Seems like the way to adjust that is at http://www.postfix.org/TUNING_README.html#rcpts.

Does the MX say how they want bulk mail delivered?

Dave