Re: draft-ietf-fax-esmtp-conneg-08.txt

> PR> Why is the CONPERM command necessary? Isn't putting Content-Convert 
> PR> parts in a message implicit permission to do such transformations? Or
> PR> is CONPERM really just signalling the server to go look inside the 
> PR> message?
> 
> Without the ESMTP option, SMTP relays must look into the message
> content, to determine whether conversion is permitted.  Hence we decided
> to put a  basic permission mechanisn into the explicit transfer
> mechanism, with the fine-grained permission detail in the content.

also, messages can be forwarded, but the permission granted by the original
sender to perform conversions might not be desired by the party forwarding the
message.  

(having the content-convert information in the message body at all seems
likely to cause problems later - ideally it should be entirely in the
envelope.  however I understand why it's in the message body.)