[ On Tuesday, March 18, 2003 at 12:07:14 (+0100), Nico Erfurth wrote: ]
> Subject: Re: [Exim] Reaction to rude 554 greeting
>
> Matthew Byng-Maddick wrote:
> >
> > I appreciate this. I think that if you're sending 554 based on who is
> > connecting then you're an enemy of reliable mail delivery. Either an
> > SMTP service runs, in which case, it should speak SMTP, and adhere to
> > the protocol, or it doesn't in which case, you've RST the connection.
>
> Hmmm, not really, because we had the discussion today .....
>
> What about outgoing/fallback only servers, which only accept mails from
> a handful of other servers?
Then either:
a) you still should speak SMTP and reject the connection _after_
the HELO/EHLO greeting command (that's one of the reasons why
there is a greeting command in the first place);
b) alternately you should use an IP firewall to return RST to
all but the "handful of other" client-SMTP hosts on behalf of
your protected server.
Any use of 5xx as a connection response is mis-use and broken,
regardless of what RFC 2821 tries to say about it.
On the sending side the only correct response to a 5xx response on
greeting is to bounce the current message (i.e. the very same as if you
get a 5xx after HELO), and if that's not what the server admin wants
then that's just too bad because that's what _MUST_ happen.
--
Greg A. Woods
+1 416 218-0098; <g.a.woods@???>; <woods@???>
Planix, Inc. <woods@???>; VE3TCP; Secrets of the Weird <woods@???>
