[RFCI-Discuss] refusing mail to abuse@ if not the only recipient

[Matus UHLAR - fantomas]

Hello,

long time ago some people commented that

- since abuse@ mail must be supported
- since spammers can try to avoid filtering by using other recipients along
  with abuse@ to avoid rejecting spam

they are using technique, that either abuse@ or other recipients are being
temporarily refused at SMTP time, which causes the same mail be delivered
twice - once for abuse@, once for other recipients, thus it's possible to
implement different filtering

-> mail to:<someone at domain>
<- 200 OK
-> mail to:<abuse at domain>
<- 4xx 

...

Which mailers support this technique and how?

I'm using sendmail and
- I'd like to know if I can implement this
- I'd like not to be listed if I won't support this.

-- 
Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
I wonder how much deeper the ocean would be without sponges.