The servers use static mappings to the same external DNS servers.
But even the most highly trained and savvy administrator can get in a hurry and make a mistake.
Also, the more experience you have, the more likely you are to make your DNS infrastructure complex, inviting the attention of Mr.
Murphy and other elements of chaotic cosmic calamity. Each network interface has a set of TCP/IP settings that lists the DNS servers used by that interface.
If the TCP/IP settings for a member computer specify the IP address of a public DNS server—perhaps at an ISP or DNS vendor or the company’s public-facing name server—the TCP/IP resolver won’t find Service Locator (SRV) records that advertise domain controller services, LDAP, Kerberos and Global Catalog.
Without these records, a member computer can’t authenticate and get the information it needs to operate in the domain.
It then acts like a teenager who can’t get the car keys, growing sullen and exhibiting a variety of bad behaviors. Let’s say you’re a VAR with a customer you plan to upgrade from NT 4.0 to Windows 2000 Server or Windows Server 2003.
The desktops use DHCP with a scope option that includes the IP addresses of two DNS servers managed by the customer’s broadband provider.
Well over 70 percent of all support calls that come to Microsoft support services that start out as Active Directory or Exchange calls end up being DNS calls.
Yet, as you’ll see in this article, most of these issues don’t require extensive diagnostic work or sophisticated tools to isolate and resolve.
I liken it to the days when automobiles had carburetors; a mechanic could fix most engine performance problems by fiddling with the choke—spritz a little WD-40 into the throttle body, charge and retire in the suburbs after a few years. Check the TCP/IP settings, run a few utilities to verify the zone records, charge 0 (correcting for inflation) and retire to Arizona.
You’ll learn to identify the most common domain name system issues that cause problems for AD and Exchange and how to avoid them in the first place or isolate and resolve them if they occur in production.