David Woodhouse wrote:
On Tue, 2005-07-05 at 09:10 -0500, wayne wrote:
In
<1120572057(_dot_)19467(_dot_)142(_dot_)camel(_at_)hades(_dot_)cambridge(_dot_)redhat(_dot_)com>
David Woodhouse <dwmw2(_at_)infradead(_dot_)org> writes:
On Tue, 2005-07-05 at 09:53 -0400, Stuart D. Gathman wrote:
<snip>
It isn't just SPF that is causing problems for forwarders in todays
email environment. Anyone who forwards email and doesn't do very
strict anti-spam measures risks being blacklisted as a spam source.
Obviously. That's hardly new.
Then why blame SPF for the problem???
Forwarding without rewriting the 2821.MAILFROM also causes problems
with bounces because the sender will receive a bounce from some place
that they never sent email to.
That's not a _problem_ though. That's just normal operation. It's worked
that way for years.
You mean *malfunctioned* that way for many years.
It can also increase backscattter.
If the forwarding host has less strict content checking in place than
the final recipient, then it can lead to backscatter, yes.
It _is_ generally content checking which causes this kind of
backscatter, in my experience -- so it's still a potential problem
regardless of SPF, BATV and other tools which attempt to validate the
reverse-path or even mail headers. Thus it's largely irrelevant to the
topic, except of course that BATV users won't be accepting those bounces
if they are generated in response to faked mail.
Besides skipping SPF checks on forwarded email, the final recipient's
domain needs to also skip spam filters/blacklisting, etc.
These are in general perfectly solvable at the forwarding site. You just
make sure your filtering is strict enough that you _don't_ end up
blacklisted, and that in general you aren't forwarding messages with
other sites would reject.
Wow, the way you say that is sounds like it is possible to accomplish.
Problem is each receiver uses different filtering and/or different
weights on rules, and sometimes change those weights, making it
impossible for the forwarder to know for all recipients of "filtering is
strict enough".
--
Terry Fielder
terry(_at_)greatgulfhomes(_dot_)com
Associate Director Software Development and Deployment
Great Gulf Homes / Ashton Woods Homes
Fax: (416) 441-9085