On 16.10.2013, at 23.34, Arnt Gulbrandsen
Not quite true. The sender often sees some anti-spam third party's server,
and only the anti-spam company talks to the real target.
There are of course reasons for why checking only the first MX server's MSMD
capability might not be enough, but hopefully people will implement the systems
in a good way that makes it a very unlikely event. The antispam servers can do
this just by having 2 different configurations (IPs) where one advertises MSMD
for their end customers that do implement it, and another one that don't, and
advertise MSMD accordingly for those IPs.
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