[ietf-dkim] Concerns about DKIM and mailiing lists

[Michael Thomas]

Dave Crocker wrote:
> 
> 
>>> I am inclined to agree.  However the [] behavior is rather common.  
>>> So we probably should consider whether it is reasonable to have DKIM 
>>> contain features that are intended to allow a signature survive 
>>> mailing list transit, when we know that the final result will usually 
>>> fail.
>>
>>
>>   That's why I use the z= option, regardless of what the
>>   overly proscriptive -base spec says. I don't think this should
>>   in any way be part of the spec though as it is clearly a
>>   heuristic and depends greatly upon how much risk a receiver
>>   wants to tolerate.
> 
> 
> 
> Use of the option seems like a reasonable idea.  However I am not sure 
> how it gets used at the validating end.
> 
> That is, I do not see what the expected scenario is, once the difference 
> between original Subject and current Subject is detected.

   It's all rather simple: if the change is "acceptable", for some value
   of "acceptable", you use the z= header instead of the actual header.
   Pretty much what Barry outlined.

		Mike