>
> I have tried that one earlier but it is not working for me, smtp_banner
> will change the message when we was trying to take the telnet, not
> effecting Email header.
>
The actual option you're probably after is
received_header_text
The details are on the URL you were originally sent.
As for removing existing received headers, that can be done on a per router basis:
http://www.exim.org/exim-html-current/doc/html/spec_html/ch-generic_options_for_routers.html
and search for headers_remove. Usual warning about being careful - this would remove all received headers. Details of header addition and removal can be found at
http://www.exim.org/exim-html-current/doc/html/spec_html/ch-message_processing.html#SECTheadersaddrem