在多域中,为提高名称解释而进行DNS重新配置

QUESTION NO: 181 (70-216)
You are the network administrator for Humongouos Insurance. The relevant portion of your network configuration is shown in the exhibit.



The network consists of four Windows 2000 domains, as shown in the following table.



DNS1 hosts standard primary zones for the domains in Los Angeles and Seattle. DNS2 hosts standard primary zones for the domains in Chicago and Atlanta. Both DNS1 and DNS2 are members of their local Windows 2000 domains. Each location has its own domain controller. The domain controllers are named L-DC1, S-DC1, C-DC1 and A-DC1.
Users in Seattle and Atlanta report that access to some network resources is extremely slow in these locations, name resolution requests sometimes take longer than one minute to process. Company management expects to add more than 150 new users to each of these locations during the next few months. You are concerned that the existing DNS servers will not be adequate to handle the new users.

You need to improve response times for name resolution requests in Seattle and Atlanta. You must also ensure that your DNS servers do not have a single point of failure. Your solution must take into consideration the expected growth in Seattle and Atlanta.
What should you do?
A. Install one new DNS server in Seattle and another one in Atlanta.
Configure each DNS server with a standard primary zone.
B. Install one caching-only DNS server Seattle and another one in Atlanta.
Configure both DNS servers to forward name resolution requests to DNS1 and DNS2.
C. Install the DNS Server service on the domain controllers in each domain.
Create a single Active Directory integrated zone for the entire forest on the DNS server in Los Angeles.
Remove the DNS Server service from DNS1 and DNS2.
D. Install the DNS Server service on the domain controllers in each domain.
Create an Active Directory integrated zone for each domain on its local domain controller.
Create secondary zones on each DNS server for each of the remote domains.
Remove the DNS Server service from DNS1 and DNS2.

Answer: D

Explanation:
In order to improve name resolution performance we install and configure DNS server at each physical location. By creating an Active Directory integrated DNS zone for each domain at the local domain controller local name resolution would not have to cross the WAN links. A further improvement and a solution to the single point of failure problem, is solved by creating secondary zones on each DNS server for each remote domain. Finally we remove the DNS Server service from the old DNS servers DNS1 and DNS2.

Incorrect Answers:
A: We must remove the single point of failure. This is not achieved with this proposed solution.
B: We must remove the single point of failure. This is not achieved with this proposed solution
Caching-only servers are used on slow WAN links, not on T1 WAN links.
C: There are several domains so we cannot create a single Active Directory integrated zone.

要提高DNS解释性能,则需要在本地安装DNS;

要防止单点失败,就要安装Secondary zones;如果有多个域,并且每个域只有一个DC时,可以在DC中为另一个域安装Secondary zones. 因为此时DNS是与DC集成的;

利用Caching-only DNS并不能防止单点失败,因为Cache Only只能解释部分名称;

Caching-only DNS 被用在慢速WAN, T1 WAN连接并无需要.

多个域中不能创建单一活动目录集成zone. (lem :为何?)