I have an internal domain as an example co.com. Co.com is a Windows 2008 domain and has an internal dns server. I have applications on the internal network that need to send email to co.com. The email server for co.com is hosted outside of the co.com network and domain. I have the mx records setup and can send email to the co.com from outside but not from inside hosts of the co.com domain. How do I make the internal DNS server for co.com send email traffic out to the mx records listed in external dns?