On May 25, 2004, at 10:24 AM, John R Levine wrote:
For instance, they are bigisp.com (this is the domain used by their
retail/residential customers), but I get spam from
x-x-x.pa.client.bigisp.com and x-x-x.nj.client.bigisp.com where the
former is covered by an SPF record and the latter is not. It would
seem that a wildcard at *.bigisp.com would help them out.
This is more of an argument for something like MTA Mark, since those
client addresses are cable modems that shouldn't be sending any direct
mail at all.
Perhaps this is an argument for MTA Mark, but I was speaking
specifically of the forward zones and not the reverse.
I also disagree with the assertion that clients on dsl/cable modems
should not be sending direct email. What they should not being doing
is sending direct email as bigisp.com (subject to the policy of the
ISP).
My point is this: there are entities doing mail administration at a
high level in their domain but may wish to have LMAP/MARID coverage on
their subdomains.
-andy