On Mar 26, 2013, at 5:50 PM, hector <sant9442(_at_)gmail(_dot_)com> wrote:
2) If squared bracketed, by specification assume a dotted IP address and by
SMTP specification this allows for a simple SMTP compliancy check to verify
the IP of the connection matches the provided IP literal. You are allowed
to do this because when a IP Literal is presented, it MUST machine the
connected client IP address. This yields a pretty high spam rejection with
100% zero false positives after at least 10 years of automated operations.
It'll fail all the time in the case of an MUA behind a NAT - which is going to
be pretty common in the case we're discussing of a dumb SMTP client submitting
to a smarthost.
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