Every website on Internet has a unique URL, which locates the website. The URL consist of the domain name, which is converted into the corresponding IP address with the help of DNS server.
You can also convert your Primary DNS server to an Active Directory Integrated Primary server, instead of adding secondary DNS servers. The concept behind adding secondary DNS server is to avoid any failure. With the following steps you can convert Primary DNS Server to Active Directory Integrated Primary server on Windows Server 2003:
STEP 1: On the current DNS server, start DNS Manager.
STEP 2: Right-click a DNS zone, click Properties, click the General tab, and then note the Type value. This will be Primary zone, Secondary zone or Stub zone.
STEP 3: Click Change.
STEP 4: In the Change Zone Type box, click to select the “Store the zone” in Active Directory check box. When you are prompted to answer whether want this zone to become Active Directory integrated, click Yes, and then click OK.
When you complete all the steps, then in the Domain properties, type will be shown as "Active Directory-Integrated". You can supplement other DNS servers in the domain controller after its replication becomes complete. So, in this way you can supplement other DNS servers, which lead to removal of any point of failure.