Re: check_badrcptto, to prevent backscatter

On 3/12/2011 3:19 AM, Todd wrote:
> Isn't back scatter exactly the intent of the spammer? Send the spam to invalid addresses with a forged return which is where the reject goes.

The reality is that spammers use forged sender addresses so their own 
accounts don't get nuked.  Relying on backscatter to get their message 
through to _somebody_ is rather pointless, because they've also spammed 
that address directly, and that most mailer bounces aren't very 
conducive to getting their message through, and most MTAs won't bounce 
in the first place.

[This may not be obvious _enough_ to those who love qmail ;-)]

It's a side-effect of forging, not a deliberate goal in itself.

> But you could be right: back scatter may be so specific that these two scripts would be the only ones ever to go into the folder.
>
> "Addresses" or "addressees" or even rcptto.

It's a much bigger issue than just backscatter.  This is the proper 
place to do anything you'd want to at rcpt-to time.  Checking for 
existence, obviously.  But also aliasing, tagged addresses, checking for 
permissible relaying, etc.  The idea is to have a single plugin that 
knows _how_ to do those things, with plugins that it in turn uses to 
find out the information it needs.