Giuliano Gavazzi a écrit :
On T 22 Jan, 2009, at 11:49 , Charles Marcus wrote:
On 1/21/2009, Giuliano Gavazzi (dev+lists@humph.com) wrote:
The postfix backscatter readme is a good start, esppecially is you are using postfix - and if you aren't, why aren't you? ;) ... but the concepts can be applied to any MTA...
I don't use postfix, because I use exim...
And as I said... the CONCEPTS can be applied to ANY MTA...
well, first of all backscatter is not really the issue of this thread.
agreed.
Secondly the concepts are not all that good.
They are ;-p
In particular the one entitled:
Blocking backscatter mail with forged sender information
that states:
"Like many people I still have a few email addresses in domains that I used in the past. Mail for those addresses is forwarded to my current address. Most of the backscatter mail that I get claims to be sent from these addresses. Such mail is obviously forged and is very easy to stop." From what I understand he is rejecting backscatter that is sent to some of his old addresses (with an identical forged sender,
Note the "from" in "claims to be sent FROM...".
but this is irrelevant) and from there forwarded to his mail server. Very bad. If you have configured forwarding somewhere you must be prepared to accept anything from there, or else you will be the cause of backscatter as the peer server is a genuine server and not a spambot.
you misunderstooood ;-p
the idea is:
if I get a bounce caused by a message sent with joe@example.com as sender, and I know joe@example.com is never used as a sender (because I own that address and I don't use it as a sender), then I can block the message.
here's another example. while my Reply-To is set to mouss+nobulk@netoyen.net, I don't use this address in From: or envelope sender. so if someone bounces a mail supposedly sent from this address, _I_ know the "original" message was a forgery and I can reject the bounce.
[snip]