I'm trying to set up email using sendmail with this guide. http://holarails.wordpress.com/2013/11/17/configure-sendmail-in-ubuntu-12-04-and-make-it-fast/
However when I try to configure it, my host name is not qualified:
WARNING: local host name (ToSO) is not qualified; see cf/README: WHO AM I?
I've tried editing the host file but it still doesn't change my host name. Could someone point me in the right direction please?