Page 59 - DCAP106_OPERATING_SYSTEM_TOOLS

Operating System Tools

Notes
Example: Consider the steps included in sending as well as receiving a letter. Your postal
carrier must know where to drop off and where to pick up mail. So your home must have some
kind of recognizable interface; we call this a mailbox. And whereas your postal carrier may know
your neighborhood quite well, delivery in other areas will require other carriers. Mail is passed
to these other carriers through a gateway; we call this the post office. Even though you can think
of the whole postal system as one big network, it’s easier to recognize if you consider it as a
hierarchy of subnetworks (or subnets): the postal system is divided into states, states are divided
into counties and cities with a range of Zip Codes, Zip Codes contain a number of streets, and
each street contains a unique set of addresses.
Computer networking mirrors this model. Let us trace an email message from you to a
workfellow. After composing the message, click Send. The message is passed to a network
interface by computer. This interface may be a modem by which you dial up an Internet Service
Provider (ISP), or it may be via an Ethernet connection on a LAN. Either way, on the other side
of the interface is a gateway machine. The gateway knows how to look at the address of the
recipient of the email message and interpret that message in terms of networks and subnets. By
means of this information, the gateway passes the message to other gateways until the message
reaches the gateway for the destination machine. That gateway in turn delivers the message
through a recognizable interface (like a modem or Ethernet link) to the recipient’s inbox.
On reviewing this, it can be easily seen which parts of networking are required to configure
on your Linux system. It is required to know the address of your machine. Just as the town
name Sebastopol and the Zip Code 95472 are two different names for the same location, you may
have both a name, called a hostname, and a number, called an IP number or IP address, that serve
as the address for your machine. IP represents Internet Protocol.
To translate among these two notations, it is necessary to know the address of a DNS (Domain
Name Server). This is a machine that matches IP addresses with hostnames. It is also necessary
to know the address of a gateway machine through which network traffic will be routed. Finally,
you will need to be able to bring up a network interface on your system, and you will need to
assign a route from that interface to the gateway.
While all of this can seem difficult, it actually is not any more difficult than the postal system, and
it functions in much the same way. Luckily, Linux comes with tools to assist you in automating
network configuration.

3.1.2 Configuring an Internet Connection

The configuration of your system is simplified by the Red Hat Linux Network Administration
Tool in order to access the Internet through a telephone dialup, DSL, ISDN, Ethernet, or wireless
connection. The Network Administration Tool needs you to follow a three-step process:
1. Set up the hardware device associated with the connection.
2. Specify DNS settings and hostnames.
3. Activate the device, if necessary.

Now we will explain how to perform these steps.

Notes All these methods of connecting to the Internet are supported by the Network
Administration tool. However, some hardware devices are not compatible with Red Hat
Linux. And, some Internet service providers insist that their customers use only Windows.
In either case, you can experience difficulties in connecting to the Internet.

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