Meng,
I am going to leave DMP enabled in our testing for another day to get most
comparison data, but it is pretty clear, the overhead of an "open domain"
lookup is much worst with DMP vs SPF. So it looks like I am going to
turn it off (DMP) soon and possible even remove it from our product antispam
testing suite before final release.
SPF itself has added atleast 1 to 3 seconds to the session time. But the
high delays are way too high with DMP to further ignore.
I am not an expert with DNS technology, but I would like know why this
would be the case. DMP does have the dual lookup for the return path
domain and machine domain. Is there a difference in that with SPF you are
searching a domain vs. DMP where you have an "in-addr" sub domain lookup?
thanks
--
Hector Santos, Santronics Software, Inc.
http://www.santronics.com