need help blocking emails to non-existent users

[Alex Broens]

On 12/19/2007 11:48 PM, Drew Marshall wrote:
> On Wed, 19 Dec 2007 22:33:46 +0000, Julian Field
> <MailScanner at ecs.soton.ac.uk> wrote:
>> Then use milter-ahead if you are using sendmail or Postfix, available
> from
>> http://www.milter.info/sendmail/milter-ahead/
>> It will cost you € 90 euros for a site licence for it, but it's well 
>> worth the small investment.
> 
> Agreed if you are running Sendmail. POstfix has this functionality built
> it. Just use recipient_verification as one of your smtpd checks and you are
> done.
>> This is a far more robust solution than trying to reliably read, parse 
>> and process all the Active Directory entries, which may be out of date 
>> on newly-created accounts, and require far more long-term maintenance 
>> than my solution above, which you can just setup and leave alone.
>>
>> Can someone add this to the wiki please?
> 
> I think you will find this is in the Postfix section already
> http://wiki.mailscanner.info/doku.php?id=documentation:configuration:mta:postfix:how_to:reject_non_existent_users
> (Watch for the wrapping)
> 

Won't recipient_verification 550 the sender if the target server is 
unreachable?
milter-ahead's action is configurable.

Alex