Office 365 and the To header

[Joseph Brennan <br...@columbia.edu>]

FYI, I have just seen email from an O 365 system with no "To:" header. "To"
has not been a required header for a long time, but still I was not aware
of any legitimate software that sends without it. Use of an empty list like
"To: Undisclosed recipients:;" must be a lost art.

This might affect scoring of the MISSING_HEADERS rule eventually. (Despite
the name it seems to mean only a missing "To" header.)


-- 
Joseph Brennan
Lead, Email and Systems Applications