Hi !!
>> If exim implements 551
>> codes it must implement both parts (client/server) and must have a
>> way to recognize if remote client supports it or not (via some
>> propietary EHLO extension)
>
> I don't think either of these is essential. Bouncing mail because user is
> actualy somewhere else is not worse than, say, bouncing it because there's no
> such user. In the first case, at least, the sender will know what to do.
if the sender get the 551 code (some MTA's just hide the real 5xx code)
and if the sender understands english and if the sender is able to
recognize the bounce error in the middle of the bounce message, most
users will just discard the bounce and the recipient will never get that
mail.
> That said, I have interest in implementing the sender part for Exim.
this would be really interesting for some situations, specially if it can
be sure (or the behaviour could be customized) that the remote client
understands (and redirects) the 551 code
>> and what about using RFC 1035 experimental 'MR' (Mail Rename) 'MB'
>> (Mailbox) and 'MG' (Mail Group) DNS records ?
>
> That seems to serve a different purpose (affecting mail sent by some senders,
> rather than mail sent by any of them).
it affects mail sent by any sender that is able to process that records
--
Best regards ...
----------------------------------------------------------------
David Saez Padros http://www.ols.es
On-Line Services 2000 S.L. e-mail david@???
Pintor Vayreda 1 telf +34 902 50 29 75
08184 Palau-Solita i Plegamans movil +34 670 35 27 53
----------------------------------------------------------------
