Re: [exim] *Suspect* reject mail for user@example.com?

2009/4/1 Tomasz Chmielewski <mangoo@???>:
> W B Hacker schrieb:
>
>
>> "Far-end destination addressee"?
>>
>> or combinations of
>>
>> selected remote <==> selected local/virtual
>>
>> ...is also possible, but needs DB or list matching, which may be
>> asymmetrically mapped (one:one, one:many, many:one, many:many).
>>
>> - and/or combined with other conditionals, such as 'Subject:', type of
>> attachment, time-of-day, .... MUA or OS used to compose the message ....
>>
>> No limits, really. I've got a rule somewhere that rejects anything
>> coming off a Winbox...
>>
>> Which do you seek?
>
> I have an Exim box which forwards certain addresses to another server, i.e.:
>
> - Exim accepts user@???
> - delivers it to server_2 for user_changed@???
>
> Now, server_2 rejects this mail for some reason (user does not exist,
> spam etc.). This means Exim will send a non-delivery report to the
> original sender. A bit too late, isn't it?
>
> This causes lots of trouble:
> - non-delivery reports get to false users (in case of rejected spam/viruses)
> - we send unnecessary non-delivery reports for non-existing users; it
> should be cut off as soon as someone connects to Exim
>
>
> I know the proper way to do it would be to have an up-to-date list of
> existing users on the Exim box for all "remote users", but it's not
> always possible.

That's a great use case for Exim's recipient callout verification. As
long as the destination server rejects unknown recipients at SMTP
time, your Exim will 'learn' (ie cache) which users are valid and
which are not and reject invalid users.

If mail is getting rejected at the destination for spam, you 'just'
need to make sure that your own spam filtering is equally or more
strict than the destination.

Peter



--
Peter Bowyer
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