Re: [Exim] HELO syntax check

On Wed, 21 Aug 2002, Philip Hazel wrote:

> On Wed, 21 Aug 2002, Paul Wilson wrote:
>
> > I'd think so too... (well, either reject on mail from or rcpt to). "550
> > Polite MTAs say hello first" would be nice.
>
> RFC 2821 says "A client SMTP SHOULD start an SMTP session by issuing the
> EHLO command." Note: SHOULD, not MUST.

That is correct. However, in the exact same section (4.1.1.1) RFC 2821
says "In any event, a client MUST issue HELO or EHLO before starting a
mail transaction". "SHOULD start an SMTP session by issuing the EHLO
command" simply means EHLO is preferable to HELO.

Paul