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

Mihamina Rakotomandimby (R12y) wrote:
> Tomasz Chmielewski wrote:
>> 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.).
>
> That happens everyday, and the only one annoyed is the one into the "From:"
> If you intend to block on "From:" you really get the risk to encounter
> false positive, seeing the quantitiy of forged "From:".
>
> I dont think it's a good idea. Why not passing it through spamassassin
> _before_ fowarding? (I dont know how yet)
>

Providing you are calling SA in the DATA phase, not 'post queue' that is
automagical. Ditto ClamAV and sputniks.

The forwarding doesn't happen until router/transports are entered, and
even there one could do post-smtp-session filtering before local or
remote delivery.

IF/AS/WHEN one needs to avoid potentially instrusive filtering AND NOT
risk upsetting the destination *server*, there are ways to 'warp' the
entire message and headers,

EG:

- 'print' the incoming message and headers to a .pdf file, send the file
to the destination as a 'safe' attachment with a one-line text-body
'transmittal' note.

- Or as a tar / zip / gz or other archive attachment. Not always as
welcome by far-end filter rules. .pdf is about as good as it gets.

These things need a lot more work to set up, but can also support fax &
voice message content.

HTH,

Bill