Re: Question about Qmail relating to MX retry processing

[Marc Perkel <marc@perkel.com>]

Harald Hanche-Olsen wrote:
> + Uncle George <qmail@gatworks.com>:
>
> | As eventually you will find that the errant spammers will find the
> | hole in your filtering scheme, and not bother with the lowest [...]
>
> AFAIK, this is already the case.  Much spam is sent directly to an MX
> other than the lowest numbered one, without bothering with the lowest
> one at all.  Imagine that - spammers intentionally violating Internet
> protocols!  8-)
>
> - Harald
>   

Yes, another trick I do is my highest MX record returns a 4xx on 
everything that connect to it. Spammers try to hit the highest one first 
thinking there's less spam filtering on it. As soon as the get the 4xx 
error they go away and never come back. I get rid of about 350,000 spams 
a day using that trick.
Which of course makes another point about the idea that if one server 
says 4xx that the other servers won't. In my case the highest MX and the 
lowest MX are on the same computer.