Hi:
I have Exchange 2010 for our company, and the accepted domain is xxx.com. It looks like sending emails within our organization does not require authentication. For example, I can send an email from ghost@xxx.com to someone@xxx.com, without being asked to enter a user name and password, and the from email, ghost@xxx.com does not even exist. How can I enforce our Exchange server to require authentication when sending emails within our organization?