On Wed, 2005-07-06 at 12:16 -0400, Stuart D. Gathman wrote:
It is not wrong, and also not problem with SPF unless all of the
following are true:
1) the target checks SPF
2) the target reject SPF failures
3) the target doesn't know who forwards to it, and doesn't whitelist them
4) the forwarder doesn't use their own MAIL FROM (e.g. SRS)
As a forwarder, you don't have to do anything unless one of your targets
starts doing 1, 2 and 3. Those targets are wrong - they should not be
rejecting when they can't list forwarders. However, you have to keep
the mail flowing, so in that case, you can compensate for their mistake
by using your own MAIL FROM via SRS or whatever for those targets (to avoid
side effects with targets that don't need it).
I agree with what Stuart says. Let's rotate the viewpoint and look at it
from the POV of the target; the final recipient.
You can observe that in general, #3 and #4 are both true. Very few
forwarding sites perform SRS and it's very hard to get details of all
possibly forwarding from your users, and it's even harder to turn that
into a list of IP addresses, which may change _daily_.
Thus you should avoid letting #2 become true. That much is within your
power.
--
dwmw2