John C Klensin wrote:
The client SHOULD send an EHLO command as the
first command after a successful TLS negotiation.
The client MUST send either an EHLO command or a HELO
command as the first command after a successful TLS
s/HELO command as/HELO command, or a command that does not
require that a mail transaction be open, as/
That can be done in several other ways, but I don't think you
can or should prohibit VRFY, EXPN, HELP, etc., there.
Just going back a step, shouldn't it be worded something like
"The client MUST send a EHLO command after a successful TLS negotiation
if it wishes to start a mail transaction or use any SMTP extensions."
Because that's actually what we mean.
Also, saying 'or a command that does not require that a mail transaction
be open' means that you could use an SMTP extension which was advertised
before the STARTTLS, as long as it doesn't involve a mail transaction,
without resending EHLO.
VPOP3 - POP3/SMTP/IMAP4/Webmail Email server for Windows