On Mon, 25 May 2009, Stefan Förster wrote:
> * Patrick Ben Koetter <p...@state-of-mind.de> wrote:
> > * mouss <mouss+nob...@netoyen.net>:
> >> and please remove the
> >> smtpd_banner = The eMail Service
> >> because it is invalid. The banner must contain the hostname... etc.
> >
> > and it must contain "ESMTP" or the client will not know the server can speak
> > EXTENDED SMTP, which includes the capability "STARTTLS", which is the
> > startpoint for TLS ...
>
> Now, maybe I'm blind, but I don't see that requirement in RFC 2821 or
> 5321. And Postfix's SMTP client's default behaviour is:
>
> $ postconf -d smtp_always_send_ehlo mail_version
> smtp_always_send_ehlo = yes
Postfix has been doing this since 2001, but that tells us nothing about how
*other* SMTP clients will act.
> I think an initial greeting of
>
> 220 fully.qualified.hostname
>
> is pretty common this days - especially with so called "anti spam,
> anti malware" appliances.
A few (admittedly superficial) tests contradict your statement:
220 smtp.google.com ESMTP
220 mta175.mail.ac4.yahoo.com ESMTP YSmtp service ready
220 mx0.gmx.net GMX Mailservices ESMTP {mx030}
220 whitehouse.gov ESMTP service at Mon, 25 May 2009 02:26:35 -0400 (EDT)
220 barracuda.barracuda.com ESMTP (bd4f6cb79ab76eb0d8a3d469f2a9f1d5)
And it's somewhat irrelevant; the point is that some SMTP clients, despite
recommendations in RFC 2821, may only send EHLO to a server that greets with
ESMTP. So it is worthwhile (and advisable) to include ESMTP in the
$smtpd_banner, unless you have a good reason to intentionally exclude it.
--
Sahil Tandon <sa...@tandon.net>
