Doubt on FETCH command

[Dilip Menon]

Hi,   When a mail if FETCHed through IMAP using ENVELOPE command, I get several fields as "NIL". What exactly do each NIL stand for?   For e.g. when I send a mail through one of the standard mail-server's smtp interface as :   data 354 start data; end with <cr><lf>.<cr><lf> MIME-Version: 1.0 Content-Type: text/plain Subject: Normal mail From: "test1" Sender: "test1" Reply-To: "test1" To: "test1"   BODY   .        the IMAP FETCH ENVELOPE returned is * 3 FETCH (ENVELOPE ("Mon, 10 Feb 2003 16:53:43 -0800" "Normal mail" NIL NIL NIL NIL NIL NIL NIL "<[EMAIL PROTECTED]>"))   What does each NIL stand for? I could not find references for this in RFC text.   Regards Dilip