Re: [courier-users] re-writing of MIME boundaries
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From: Sam V. <mr...@co...> - 2012-02-27 00:47:05
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Mike Korizek writes: > On 02/26/2012 12:09 PM, Mike Korizek wrote: > > Hi all > > > > If courier receives an email with plain/text and HTML parts there happens > a re-writing of the MIME boundaries. > > If the email is digitally signed first, the verification fails due to this > re-writing. > > > I checked the source of the email - the content type is set correctly, > as multipart/signed. But does it also properly specify "Mime-Version: 1.0"? > Why does courier touch/change this email at all? The contents of multipart/signed should not get altered, but other parts of the mail that are not inside the multipart/signed scope, such as the top- level headers, may be rewritten. There may be several reasons for rewriting headers. If the content type does not specify an explicit character set, the system default character gets explicitly added to the headers. Or if the headers specify 8 bit transfer encoding, but the message does not actually content 8 bit content, the transfer encoding gets reset to 7 bit. Or, even more importantly, when sending a message with 8 bit transfer encoding to a mail server that does not advertise 8BITMIME, the message must be converted to quoted-printable. Except when it's multipart/signed, and mail user agents, for those reason, should not use 8 bit transfer encoding for signed content. |