Avoiding qmail from accepting messages to any user regardless of the existence.

[Vini <vini@xxxxxxxxxxx>]

Hi guys,

I am just curious to know how you guys deal/solve the qmail's "problem" 
of accepting any message to a valid domain regardless of the existence 
of a mailbox. Given that more than a half of the emails today is junk 
mail this has turned into a problem as qmail has to bounce all the 
messages sent to invalid users which makes it waste bandwidth and server 
resource and could even lead to a joe-job.

I know two patches that would solve this problem which are - recipients 
extension included in spamcontrol and CHKUSER which uses vpopmail.
In my case CHKUSER would be the most suitable one as I am using vpopmail 
 as my qmail's back-end.

Although I do know how to solve the problem I would like to hear from 
you guys how it has been solved on your qmail and which would be the 
most advisable way to solve it in your opinion.

Thanks a lot,
Vini