Author: David Woodhouse Date: To: exim-users CC: Paul Wilson, Chris Edwards Subject: Re: [Exim] HELO syntax check
ph10@??? said: > RFC 2821 says "A client SMTP SHOULD start an SMTP session by issuing
> the EHLO command." Note: SHOULD, not MUST.
That's because you don't actually have to send mail in every SMTP session.
If you're going to try to send mail, you MUST use EHLO first (§4.1.4):
A session that will contain mail transactions MUST first be
initialized by the use of the EHLO command. An SMTP server SHOULD
accept commands for non-mail transactions (e.g., VRFY or EXPN)
without this initialization.
It doesn't say you SHOULD accept commands for mail transactions, only
non-mail transactions.
