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.
Secondly the concepts are not all that good. 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, 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.
The old Postel rule Be conservative with what you send and liberal
with what you receive (or something on those lines) might be too
liberal in the current internet, but certainly should not be relaxed
on the conservative part... The first thing an administrator should
look for is to avoid generating spam of any sort, then he can think of
ways to stop it (and even more responsibly to place a further burden
on spammers with delays and the like, but this is something you can
only do on an MTA).
Giuliano