Hello. We have a Windows 2003 R2 domain. We have 2 servers for Active Directory. One server is a DHCP server, both are running Windows DNS services. The DHCP lease pool points to both servers for DNS resolution; 192.168.1.6 as preferred and 192.168.1.5 as alternate. Recently, some internet domains will not resolve. If I remember correctly, I read where you shouldn't use your ISP's domain servers with AD. I could be wrong. If I change the DHCP lease pool option to point to Cox's domain servers, internet domains resolve properly. Can anyone tell me why they won't when using internal DNS servers? They've worked for years without issue. Nothing has changed on the servers. I thought once a dns query was made to the internal DNS, if it couldn't find a host, it referred to the ISP's domain automatically. I don't understand why typing in the DNS works. We only have one provider, Cox. I appreciate your help.