who's producing Message-ID?

[Song Jianping]

Hi all,

I think it is the MTAs, such as sendmail, that produce Message-ID for
the mail.

Can i assign Message-ID myself? I know the mail client "mutt" allow
someone to add headers via "my_hdr FieldName: Value". When i assign
Message-ID for my message, sendmail will always generate another
Message-ID for me, which produces a mail with two Message-ID headers.
Can i disable the function of Sendmail? I am using RedHat6.0.

Thank in advance.
---- 
Best Regards
Song                                     mailto:[EMAIL PROTECTED]