Nonexistent Users

Alan Dobkin MailScanner at
Fri May 6 14:48:11 UTC 2016


Ideally, your MTA (Postfix, Sendmail, etc.) should reject mail to 
non-existent accounts during the initial SMTP transaction, before 
MailScanner ever sees it. See page 8 of the MailScanner guide book for 
an overview of how it works, available here:

If you provide more details on your server configuration, someone here 
may be able to point you in the right direction. For example, with 
Postfix, see:

> Rejecting mail for a non-existent recipient address. This form of 
> ingress filtering helps to keep the mail queue free of undeliverable 
> MAILER-DAEMON messages. This requirement is enabled by default 
> ("smtpd_reject_unlisted_recipient 
> <> 
> = yes").

If you are relaying for other mail servers, you may also want to enable 
recipient address verification:


On 5/6/2016 9:45 AM, Jim Wirtz wrote:
> Is there a way to configure  MailScanner to not process email to 
> nonexistent users/accounts?
> My server spends a lot of CPU time  to check/process emails that are 
> just going to be deleted.
> Thanks....
> Jim
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