On 05/13/14 03:02 PM, Stephan Bosch wrote:
Use of NULL envelope sender is generally recommended to prevent mail loops
Unfortunately, many servers out there reject emails with NULL sender.
Some recent examples (real server names edited) :
... while talking to antispam1.*.ca.:
>>> DATA
<<< 550 Empty envelope senders not allowed
... while talking to smtp.*.net.:
>>> MAIL From:<> SIZE=1096
<<< 550 5.1.0 <> Blank From: addresses are not allowed. Please provide
a valid From: IB501 <http://x.co/srbounce>
... while talking to spam.*.edu.cn.:
>>> DATA
<<< 553 Requested action not taken: NULL sender is not allowed
... while talking to mail.*.co.kr.:
>>> MAIL From:<>
<<< 501 bad sender address expression.
... while talking to antispam.*.com.:
>>> MAIL From:<>
<<< 501 Syntax error in address
