Hi,

no matter which process will be chosen next the following small
correction should be considered:

According to the mails below the RFC compliant change of content
encoding in MTA-forwarding may break signatures that follow the RFC 4871
recommendation to include header "Content-Transfer-Encoding" in the
signature. This header should be removed from section 5.5. Recommended
Signature Content (The following header fields SHOULD be included in the
signature ...).

Regards,
Florian



Wietse Venema schrieb:
> Florian Sager:
>   
>> Hi Wietse,
>>
>> I'd like to get your evaluation of the following aspect before
>> discussing this on the DKIM mailing list, maybe:
>>
>> In the context of testing DKM monitoring services in
>> http://www.dkim-reputation.org we experienced that postfix changed
>>
>> an incoming Content-Transfer-Encoding: 7bit
>> to
>> an outgoing Content-Transfer-Encoding: quoted-printable
>>     
>
> See RFC 1652 section 3.
>
> When sending 8BITMIME into a software that does not support 8BITMIME,
> the sending mail system must convert to 7bit or return the mail.
>
> You can turn this off in YOUR Postfix, but that really does not
> prevent other RFC-compliant mail systems from converting to 7bit.
>
> See also: http://www.postfix.org/FILTER_README.html section "
> Advanced content filter: sending unfiltered mail to the content
> filter" for how to avoid conversions with stupid content filters.
>
>       Wietse
>
>   
>> The DKIM signature in the mail was broken afterwards, 'cause the Content-T
>> -ransfer-Encoding header was included like it's proposed in http://www.ietf.o
>> -rg/rfc/rfc4871.txt, 5.5.  Recommended Signature Content (The following heade
>> -r fields SHOULD be included in the signature ...).
>>
>> I guess that changes in the encoding are allowed in forwarding mail so the
>> - DKIM header inclusion recommendation might be erroneous?
>>
>> Regards,
>> Florian
>>
>>
>> ===
>>
>> Agitos Websolutions
>> Florian Sager, Bernhard Heindl und Christian Heindl GbR
>> Stifterstrasse 16, 83026 Rosenheim
>>
>> Telefon: 089/45867554
>> Telefax: 089/45867555
>> Support: [email protected]
>> http://www.agitos.de
>>
>>
>>
>>     
>
>   

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