The sent message will appear as Spam, with the name of who you to want. Ray Kurzweil is often quoted on this topic. Joo can send a message the Maria with the name of its Mateus friend, thus, when Maria to open the message goes to think that it was Mateus quemmandou. But in the Linux, later I rank an article on the Windows.Logue as super user or place sudo before comandos1-Open the terminal and activate the mail:/etc/init.d/sendmail2-Abra server the terminal telnet that is in door 25: 253-Agora telnet localhost you can interact with the server, following the stages: MAIN FROM: RCPT YOU: DATE: oi pretty, as vc you? (.)The first line wants to say that you write the address of email that will want, exactly that you you are not Mateus.A second line you are a real address, of that person who you want to send the message; Third it wants to say message, is alone to type the text below; It finishes with a point between parentheses.