At 12:50 PM 10/17/2008 -0400, Stuart D. Gathman wrote:
On Fri, 17 Oct 2008, Alessandro Vesely wrote:
Doesn't that assume "+mx -all"? One should whitelist the IPs where replied
messages actually came from... Rather, I would whitelist the sender and just
flag the DNSBL lookup response, delaying any reaction until responding to the
RCPT command. That way it is also possible to forget DNSBL altogether for
specific recipients who don't want that filtering.
Senders change their IPs. If they have an SPF record, this is transparent.
For important senders with no SPF record, I can create a local one manually
to positively identify them.
How many of these records do you maintain? How much time does it take?
I do this only for the largest senders, like yahoo.com. It's a tough choice -
manual labor to keep up with the sender's changes, or risk losing their
messages in the spam filter.
What is the problem with these senders? What will it take to motivate them?
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