Re: name and filename parameters

Keith Moore <> Sat, 21 June 2008 14:08 UTC

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Date: Sat, 21 Jun 2008 10:08:16 -0400
From: Keith Moore <>
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To: Francesco Gennai <>
Subject: Re: name and filename parameters
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as far as I know, the name parameter is only defined for the 
application/octet-stream content-type.  content-disposition is the 
standard way to associate a filename with a MIME body part.

many user agents have supplied a name parameter with other 
content-types, but this is not standard and never has been. 
content-disposition was defined some time after the original MIME 
specifications that defined the name parameter for 
application/octet-stream, so many user agents borrowed the name 
parameter for use with other content-types.

RFC 3851 appears to be recommending nonstandard behavior, though it is 
probably mostly harmless.


Francesco Gennai wrote:
> Question about composing a MIME part where I would suggest
> also the file name.
> Question:
> In the case that I would suggest a file name to the remote
> MIME client could I use only the name parameter of the content-type
> or MUST I add the content-disposition header with the filename parameter?
> My doubt come also from the following sentence in RFC3851
> (Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1
>                          Message Specification):
> .. ..... .
> 3.2.1.  The name and filename Parameters
>    For the application/pkcs7-mime, sending agents SHOULD emit the
>    optional "name" parameter to the Content-Type field for compatibility
>    with older systems.  Sending agents SHOULD also emit the optional
>    Content-Disposition field [CONTDISP] with the "filename" parameter.
>    If a sending agent emits the above parameters, the value of the
>    parameters SHOULD be a file name with the appropriate extension:
>  .... ..... ... 
> where a system using only the name parameter is considered an "old system".
> So, I don't understand if "old system" is related to some old S/MIME
> system, or to a generic old MIME system....
> Francesco