On 10/28/2014 12:47 AM, Hosnieh Rafiee wrote:

I have tried even to forward and reply (change the sender to myself) of another message to myself. The header did not contain any reply to. Whatever happens is in IETF part and not the MUA in my side.

But in any case, I have started a new message. My message did not have any similarities to the other message except, it might be a word "privacy" in subject or content. Besides that there was no similarity.

Exactly what do you mean by "started a new message"? If you mean you selected 'new', 'write', 'mail', 'compose' or whatever you do in your mail client to compose a brand new message, then that message should be sent with no References: or In-Reply-To; headers.

On the other hand, if you start with 'reply', 'reply-all', 'reply-list' or similar, even if you subsequently remove and replace everything in the visible message headers and body, the message you send is still a reply and will contain whatever References: and/or In-Reply-To; headers that your client normally includes in replies.

-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan