So I have a client running a Server 2008/Exchange 2009 box, which is set as the DNS and domain controller. He is using a local T1 company, and their router is working as DHCP. During the initial setup, we realized that if the server was not set as the primary DNS on a local computer, then exchange was unable to connect. So I said no big deal, and set the DNS server, and all was well. Now the customer is having issues with internet speeds and the T1 company is blaiming it on our windows server. So in order to prove that it is their issue and not ours, we need to be able to set their router as DNS without losing exchange functionality. Any help would be appreciated!