I currently have postfix setup on a ubuntu machine which I am using as a mail relay. I have tested it to make sure it works fine sending mail but now I have a question. I want to send an email from just the name John. However when I type "MAIL FROM: John" When I receive the message I can see that postfix appended the myhostname variable (located in /etc/postfix/main.cf) onto the end of it. I tried changing that variable and leaving it blank in the file but it wouldn't allow me to save this change. Any ideas on how to acomplish this?

Thanks,
John