Alan Boyd:
> Hello,
>
> I'm trying to find a way to reject email which is sent to an unknown
> user (determined by an external program) at a virtual domain, such
> that the email doesn't even enter the mail queue.
>
> Currently, my set up is as follows:
> I use a virtual mapping to send email in the format
> [EMAIL PROTECTED] to a localuser.
> In my aliases file, email to localuser is piped to an external program
> for delivery.
>
> I can set up my external program to return a sysexit code of 67 so
> that a bounce message is sent back to the sender. But since I'm using
> a catchall email address, this would result in a very large number of
> bounce messages being sent due to the spammer 'shotgun' approach of
> trying to find valid addresses. I'd much prefer it if I can find a way
> to query the address early on so that an email to an unknown user is
> rejected and doesn't even get in to the mail queue.
>
> Any clues on how this might be accomplished? I can change my external
> program as desired and the 'valid' email addresses are variable (and
> fairly large) but known.
For Postfix to reject invalid recipients at the SMTP port, this
information must be available as a lookup table. You will have
to use one of the supported database types: file, SQL, LDAP, and
so on, or add your own table lookup mechanism.
See "man 1 postconf", option "-m".
Wietse
