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Subject: Re: smtpd_banner without ESMTP
From: Lutz Jaenicke (Lutz.Jaenickeaet.TU-Cottbus.DE)
Date: Tue Mar 07 2000 - 07:06:24 CST

On Tue, Mar 07, 2000 at 03:57:12PM +0300, Anand Buddhdev wrote:
> On Tue, Mar 07, 2000 at 01:18:33PM +0100, Rask Ingemann Lambertsen wrote:
> > To save 6 bytes of outgoing bandwidth for each SMTP connection we get?
>
> Instead of taking out the ESMTP, why don't you remove the hostname. I
> once setup an MTA to advertise
>
> 220 ESMTP
>
> only. We still advertised ESMTP, but saved some bytes nevertheless. I
> know the RFCs require the hostname to be present, but I never observed
> any ill-effects of removing it.

With all due respect, I don't think we should recommend violating fundamental
RFCs as RFC821. The actual discussion to this topic should demonstrate how
much hassle is created by not following RFCs. Probably postfix (and other
software) could be far simpler if RFC violation could simply be punished
by denying the service. But we cannot do it, because we want to send and
receive mails.

As a technical addendum: The " ESMTP" (six characters) is sent within one
TCP packet together with the whole greeting, you also have to consider TCP
handhaking, so probably the net effect of not advertising ESMTP will be
approximately zero.

Best regards,
        Lutz 

-- 
Lutz Jaenicke                             Lutz.Jaenickeaet.TU-Cottbus.DE
BTU Cottbus               http://www.aet.TU-Cottbus.DE/personen/jaenicke/
Lehrstuhl Allgemeine Elektrotechnik                  Tel. +49 355 69-4129
Universitaetsplatz 3-4, D-03044 Cottbus              Fax. +49 355 69-4153