You of course understand that this is not possible, right?
On Thu, Jul 22, 2010 at 6:50 PM, Wietse Venema <wie...@porcupine.org> wrote: > Vasya Pupkin: >> I'm doing best I can to fight spam. > > Then you will have to predict what mail will be rejected down-stream. > Let me know when you solve that problem :-) > > Wietse > >> that pierced through all filters. There is no 100% way to detect spam >> and you know that. So, some percentage will still go through and will >> be forwarded, and possibly rejected, causing bounce to be generated. >> >> On Thu, Jul 22, 2010 at 6:27 PM, Wietse Venema <wie...@porcupine.org> wrote: >> > Vasya Pupkin: >> >> Hello. >> >> >> >> First, I have spent two days reading articles and searching web for >> >> solution but failed there. I am using postfix as an mx for my domains, >> >> it accpets mail for different addresses withing my domains which is >> >> then forwarded to other external domains, i.e. google.com and other >> >> mail services. Mail for unknown users is rejected, many other check >> >> are performed, but still sometimes my system acts as a backscatterer >> >> when something like this happens: >> >> >> >> 1. Incoming mail passes all tests, it's coming to one of the addresses >> >> within my domain, i.e. existing-u...@mydomain.tld >> >> 2. Postfix then forwards mail to external domain, i.e. >> >> myem...@mailservice.tld >> >> 3. For some reason mailservice.tld rejects this mail, i.e. it doesn't >> >> like it's content or size. >> >> 4. Postfix then bounces mail to sender, which can be forged, and thus, >> >> becoming a backscatterer. >> >> >> >> Is there any way to prevent postfix from sending bounces anywhere? >> > >> > The best conutermeasure is not to forward spam. >> > >> > The second-best solution requires the ability to predict if a >> > specific message will be rejected down-stream. Let me know when >> > you solve that, so I can add it to Postfix. >> > >> > ? ? ? ?Wietse >> > >> > >
