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3 Planning Internet
Connectivity
Exam Objectives in this Chapter:
■
Plan an Internet connectivity strategy.
■
Troubleshoot connectivity to the Internet.
❑
Diagnose and resolve issues related to Network Address Translation (NAT).
❑
Diagnose and resolve issues related to name resolution cache information.
❑
Diagnose and resolve issues related to client configuration.
Why This Chapter Matters
In this chapter, you learn about developing an Internet access strategy that
enables your network users to access the services they need efficiently and
securely. To connect a network to the Internet, you must select an
appropriate
connection type based on the network’s requirements, determine what IP
addresses you will use on your client computers, and decide how you will
protect
the network from Internet intruders.
Although it is easy to connect a network to the Internet, doing so with
appropriate
security complicates the process considerably. This chapter examines the
various
types of shared Internet connections you can use for a network, describes
how to
evaluate a network’s Internet access needs, and describes the methods you
can use to
protect the network from Internet predators. When planning an Internet
access solu-
tion for your network, you might think that the security hazards in your
situation are
minimal and that the potential for abuse of the Internet connection by your
own users
is not an issue. Many network administrators feel this way at first and
subsequently
change their minds, usually when something bad happens. It is a good idea to
con-
sider these factors at the start so that you can implement an Internet
access solution
that is sufficient and secure, before you lose any money or data.
Lessons in this Chapter:
■
Lesson 1: Planning an Internet Connectivity Infrastructure . . . . . . . . .
. . . . . 3-3
■
Lesson 2: Selecting Routers and ISPs . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . 3-15
■
Lesson 3: Securing and Regulating Internet Access . . . . . . . . . . . . .
. . . . . . 3-24
■
Lesson 4: Troubleshooting Internet Connectivity . . . . . . . . . . . . . .
. . . . . . 3-34
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