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Recently we are creating an application for interpreting email contents, this application shall give us the TO addresses, CC addresses and BCC addresses.

When handling BCC field, we found it seems not able to get BCC addresses directly. Referring to RFC2822, MORE QUESTIONS arise.

 " There are three ways in which the "Bcc:" field is used. 
   In the first case, when a message containing a "Bcc:" field
   is prepared to be sent, the "Bcc:" line is removed even 
   though all of the recipients (including those specified
   in the "Bcc:" field) are sent a copy of the message...

   Finally, since a "Bcc:" field may contain no addresses, a 
   "Bcc:" field can be sent without any addresses indicating
   to the recipients that blind copies were sent to someone. "

Suppose an email is sent out as below adddresses

   To: to1@address.com
   cc: cc1@address.com 
   bcc: bcc1@address.com

My questions are, when the recipient bcc1@address.com received its email, will there a "bcc1@address.com" in the email source file? If yes, then what field it is placed? If not, then how is it possible for this email to the recipient when there is no any information about the "bcc1@address.com"??

[update]
how can the email server know whose mailbox to deliver this email to, if the email message contains no information about the BCC recipient's email address, including the header part? how a server correctly forwards such an email?

Community
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Wallace
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1 Answers1

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The content of an email does not necessarily contain any information about its recipients. During message transport, this information is carried in the message envelope, which is then discarded on delivery.

What you are pursuing cannot be done reliably (although many person-to-person messages obviously contain the information in the headers).

Many mailing list messages are good examples, especially those which are delivered to multiple recipients in the same domain.

tripleee
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  • Also, this is a major FAQ. You cannot have googled a lot before asking here. – tripleee Nov 07 '15 at 06:44
  • Historically, there were implementations which interpreted the spec to mean that Bcc recipients were allowed to see this header, and so it was only removed from the non-Bcc copies of the message; but I have never seen a real-life example. – tripleee Nov 07 '15 at 06:49
  • what I can't directly get by googling is, "if it is possible that an email being delivered to some recipient even when the email contains no information about the recipient? How would such an email be sent to the recipient's mailbox " – Wallace Nov 07 '15 at 13:28
  • I explained that in the answer; is there something you need help understanding still? – tripleee Nov 07 '15 at 13:30
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    Not exactly, but that's the general idea. Think of paper mail in an envelope; your secretary extracts the message from within the envelope, and delivers just the letter. He has not modified the actual letter when you receive it. – tripleee Nov 07 '15 at 13:40
  • sorry, I reread you post and try to understand it. does it mean that such an email would be sent to the BCC recipient's mail server, containing all information including the BCC recipient's address, but after arriving at the BCC recipient's mail box, the information was then removed? – Wallace Nov 07 '15 at 13:41