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.
Cheers!
