I've setup an Exchnage 2013 server. Internal emails are flowing fine. But there's some problem with external emails. Whenever I send emails to external domain I get the message that my IP is not authorized to send the emails directly and that I should relay to some other SMTP server. Hence I created a custom connector with smart host and used GoDaddy's smtp server address for the same. Still, whenever I send emails, my public IP is shown to the receipient and it refuses the email. What could be the solution?