Microsoft windows 2000 DNS manual YYY corporation ZZZ corporation VPN Firewall

A computer in the ZZZ Corporation needs to resolve a DNS query for www.zzz.com. It submits the query to the assigned DNS server (Step 1). If its cache contains the necessary data, the server will respond to the client. Otherwise the server forwards the query to the DNS server containing the zzz.com. zone (Step 2). Since the server is authoritative for the name www.zzz.com. it resolves the query and returns the response to the client through the forwarding DNS server (Steps 3-4). At this point it is important to emphasize the significance of the fact that the zzz.com. zone on the internal DNS server contains both internal and external names. If it contained only internal names then this query would not be resolved and name error would be returned to the client.

Finally, consider an example of a corporate computer that needs to resolve a host name from the private namespace of a merged company.

.

com.

yyy.com.	zzz.com.	someother.com.
	External world / Global Network

YYY corporation
Proxy Server	VPN

4

	5
	.
2	yyy.com.
3

YYY corporation

ZZZ corporation

VPN Firewall

ZZZ
corporation	2
	zzz.com.
	yyy.com.
	3

first.yyy.com. second.yyy.com. third.yyy.com. first.zzz.com. second.zzz.com. third.zzz.com.

1 6 1 4

Zone.Name. Primary Zone

Zone.Name. Secondary Zone

A DNS Server, Firewall, VPN or Proxy Server A DNS Client

A computer in the YYY Corporation needs to contact a computer myname.zzz.com.

Windows 2000 White Paper 54