Re: [exim] RFC 5321, 5322

--On 3 October 2008 15:30:08 -0400 Marc Sherman <msherman@???>
wrote:

> Jeroen van Aart wrote:
>>
>> "Bounces should only be sent if the receiver knows they'll be "usefully
>> delivered." This is code for: Don't sent bounces when your system
>> rejects spam or virus traffic, or you'll become an Internet pariah."
>>
>> That sounds nice in theory. But how can you ever in a sane manner
>> determine with reasonable certainty a bounce will be usefully delivered?
>> If you try to make this work it makes it also more likely legitimate
>> bounces will not be sent out. Which in turns conflicts with:
>>
>> "Silently discarding messages is not prohibited, but it is strongly
>> discouraged."
>>
>> Or am I missing something totally obvious?
>
> Yes. It means, "reject spam at SMTP time, not by accepting and bouncing.
> Only accept messages at SMTP time that you believe you can successfully
> deliver."
>
> - Marc

I think it's a bit more subtle than that. You can determine with reasonable
certainty whether a bounce message can be delivered to a local user. So, I
think this means:

If this is inbound email, with a remote sender, then reject at SMTP time if
you don't want to deliver it. If it's a local submission, then you may
prefer to accept then bounce.

Why would you prefer to accept, then bounce? Because some MUAs (eg, PHP
scripts) don't handle rejection very well.


--
Ian Eiloart
IT Services, University of Sussex
x3148