Re: [Exim] Failing behviour based on SMTP codes.

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Author: Philip Hazel
Date:  
To: Theo E. Schlossnagle
CC: exim-users
Subject: Re: [Exim] Failing behviour based on SMTP codes.
On Tue, 10 Oct 2000, Philip Hazel wrote:

> Oh, wait. Are you saying you get a 550 upon connection? Or in response
> to the EHLO command? In those cases, yes, Exim treats it as a problem
> with the host, and will try the message again later. Maybe it shouldn't.
> Maybe that should be configurable, but at present it isn't.
>
> Maybe I should make that kind of error one of the ones that can be
> recognized in retry rules, so you could chose exactly what is done.
> Noted for the list.


I've looked at the code. Exim was treating any error before it sent MAIL
FROM as a temporary, host-specific error. On thinking about it, I've
decided this is wrong. I have therefore made the following change to the
development source:

9. Exim was treating a 5xx response on connection to an SMTP server, or in
response to HELO, in the same way as a connection failure - that is, as a
temporary error, causing the message to be tried again later. It now bounces
all the addresses in these situations.

[Note for the purists: a 5xx response to EHLO causes it to try HELO,
which is why it says HELO there rather than EHLO.]


A Question For The List:

This seems the Right Thing in the case when there's only one host
involved. It is less obvious in the case where the domain routes to two
hosts, and the first one that is tried gives one of these 5xx codes. Do
you try the other host? With this new code Exim does not. This is the
same behaviour as happens with a 5xx response to MAIL FROM or RCPT TO,
and I think it's the right thing to do, but do you agree?

-- 
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.