SMTP and the cc header - TCP-IP

This is a discussion on SMTP and the cc header - TCP-IP ; My question is about the relationship between the SMTP "RCPT TO" command, and the "cc" header field. Does SMTP acknowledge the "cc" header field in any way at all? Or is it completely up to the MUA to extract all ...

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Thread: SMTP and the cc header

  1. SMTP and the cc header

    My question is about the relationship between the SMTP "RCPT TO"
    command, and the "cc" header field. Does SMTP acknowledge the "cc"
    header field in any way at all? Or is it completely up to the MUA to
    extract all the addresses in the cc header field and convert them into
    "RCPT TO" commands when talking with an SMTP server?


  2. Re: SMTP and the cc header

    In article <1180824308.593607.127870@q75g2000hsh.googlegroups. com>,
    wrote:
    >My question is about the relationship between the SMTP "RCPT TO"
    >command, and the "cc" header field. Does SMTP acknowledge the "cc"
    >header field in any way at all? Or is it completely up to the MUA to
    >extract all the addresses in the cc header field and convert them into
    >"RCPT TO" commands when talking with an SMTP server?


    Completely up to the MUA.

    It might help to consider what happens for the procesing of Bcc.
    It isn't the case that MTAs are conscientious about stripping
    Bcc addresses out before the destination users see them: Bcc
    addresses are literally not sent in the body, and only show up in
    the form of RCPT TO commands.


  3. Re: SMTP and the cc header

    In article <1180824308.593607.127870@q75g2000hsh.googlegroups. com>,
    wrote:

    >My question is about the relationship between the SMTP "RCPT TO"
    >command, and the "cc" header field. Does SMTP acknowledge the "cc"
    >header field in any way at all? Or is it completely up to the MUA to
    >extract all the addresses in the cc header field and convert them into
    >"RCPT TO" commands when talking with an SMTP server?


    MTAs (mail transfer agents) care only about the envelope including the
    Mail_From and Rcpt_To values. The cc: header field inside the envelope
    matters to MTAs as little as a "cc:" line in paper mail message matters
    to the U.S.Postal Service. The U.S.Postal Service or MTA care only
    about the recipient and return addresses on the envelope. You say "send
    this letter to Joe with a carbon copy to Joan and a blind carbon to
    Sam," and your secretary or MUA prepares the envelopes and gives them
    to the postman or MTA.


    Vernon Schryver vjs@rhyolite.com

  4. Re: SMTP and the cc header

    I see. Okay thanks for clearing that up for me.


  5. Re: SMTP and the cc header

    In article ,
    Vernon Schryver wrote:

    >MTAs (mail transfer agents) care only about the envelope including the
    >Mail_From and Rcpt_To values. The cc: header field inside the envelope
    >matters to MTAs as little as a "cc:" line in paper mail message matters
    >to the U.S.Postal Service.


    Though, some anti-spam filters -do- care about the headers that appear
    in the body of the message, and as those anti-spam filters may be
    built in to the MTA, it is not categorically correct to say that
    MTAs care only about the envelope. Caring only about the envelope is
    the idealized model; looking at the body is the corrupt but
    necessary practice.

  6. Re: SMTP and the cc header

    In article ,
    Walter Roberson wrote:

    >>MTAs (mail transfer agents) care only about the envelope including the
    >>Mail_From and Rcpt_To values. The cc: header field inside the envelope
    >>matters to MTAs as little as a "cc:" line in paper mail message matters
    >>to the U.S.Postal Service.

    >
    >Though, some anti-spam filters -do- care about the headers that appear
    >in the body of the message, and as those anti-spam filters may be
    >built in to the MTA, it is not categorically correct to say that
    >MTAs care only about the envelope. Caring only about the envelope is
    >the idealized model; looking at the body is the corrupt but
    >necessary practice.


    MTAs acting according to RFC 2821 care only about the envelope.
    However, U.S. Postal Service Inspectors, law enforcement officials,
    and other interested parties snoop on the contents of envelopes and
    commit various other layering violations of varying necessities and
    degrees or kinds of corruption.


    Vernon Schryver vjs@rhyolite.com

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