Re: [Exim] Reaction to rude 554 greeting

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Author: Exim Users Mailing List
Date:  
To: Exim Users Mailing List
Subject: Re: [Exim] Reaction to rude 554 greeting
[ On Saturday, March 15, 2003 at 18:41:53 (+0000), Giuliano Gavazzi wrote: ]
> Subject: Re: [Exim] Reaction to rude 554 greeting
>
> First, we are not talking of generic 5XX but of the specific 554.


Regardless the only correct thing for the sending-SMTP to do is to
bounce the current message it's trying to deliver and then to cache the
fact that a delivery attemtp to this host failed and to not retry any
connection to that host for at least 30 minutes.. It is up to the user
(and, at his or her request, the postmaster) to decide what to do.

> In particular 554 at the connection opening (greetings) phase (that
> is the issue of this thread) does NOT mean a generic "go away" but
> "No SMTP service here". That's a hell of a difference.


It's only a difference to the human diagnosing the problem, not to any
sending-SMTP. The second and third digits of the response code MUST NOT
change the steps it takes in bouncing the message (only perhaps in what
additional information it includes in the bounce).

> 554 at greetings does not seem the appropriate place for enforcing an
> IP rejection policy.


Indeed! No variant of a 5xx response at greeting is appropriate as a
way to implement an IP rejection policy.

The correct way to reject SMTP clients by IP# is to reject them at the
time they issue their greeting command (HELO/EHLO).

--
                                Greg A. Woods


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