Slightly OT: Postfix smtpd restrictions

[Ram]

On Thu, 2010-06-24 at 12:57 +0100, Jason Ede wrote:
> This is purely MTA based, but since a lot of users here run postfix...
> 
>  
> 
> How have others found reject_unknown_reverse_client_hostnameand the
> more harsh reject_unknown_client_hostname in postfix? I’m debating
> implementing them here and wonder if others have found them
> problematic or useful? I thinking they should be good for weeding out
> spam emails and I can’t see that they should catch legitimate senders,
> but want to be sure.
> 

That sure catches a lot of mails sent directly from BOTs.  If you have
multiple MX servers use them only on the lowest MX, If any legitimate
mail is rejected then they would retry on the higher MX 

This is what I do , but I am not sure I can say it has helped for sure,
because BOTs too can retry