Dave Crocker wrote:
Tony Finch wrote:
"The "Sender:" field specifies the
mailbox of the agent responsible for the actual transmission of the
Popular MTA implementations (Sendmail, Postfix) do not implement the
Sender: header the way 822 and 2822 suggest,
How would you describe what they do do?
Well, if SendMail/PostFix is operating like the rest of the world... If
missing, a SMTP receiver MIGHT do:
Sender: <-- x821.MailFrom
in the same vain many SMTP receivers will fill in the missing 822
FROM: <<-- x821.MailFrom
To: <<-- x821.RcptTo
and they MUST do this if they want to SUPPORT the presentation layers.
But sender is not a given because it is not a 822 required field. In
fact, I seem to recall, it was only in recent years that we even
bothered with Sender in our mailers.
Only a few sites will reject such empty headers in the DATA block. Off
hand, I know of one, HOTMAIL.COM and they only started to reject mail
without the headers when SENDER-ID support was added to HOTMAIL.COM.
Hector Santos, CTO
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