Red Hat Linux Networking , System Administration (P4) ppsx

The remainder of the Boot Loader Configuration screen gives you the option to select the disk partition from which you want to boot the PC.. Configuring the Network If the Linux kernel d

The screen includes a General Kernel Parameters text field that enables you

to enter any special options that Red Hat Linux may need as it boots Yourneed for special options depends on what hardware you have

The remainder of the Boot Loader Configuration screen gives you the option

to select the disk partition from which you want to boot the PC A table then liststhe Linux partition and any other partitions that may contain another operatingsystem If your system has a Linux partition and a DOS partition (that actuallyhas Windows 95/98 installed on it), the table shows both of these entries Eachentry in that table is an operating system that the boot loader can boot

After you install the boot loader, whenever your PC boots from the harddisk, the boot loader runs and displays a screen showing the operating sys-tems that you can boot The default selection will be highlighted and will bootautomatically after a few seconds You may move the highlight bar to thename of another operating system to boot (The Boot label column in the table

in the center section of Figure 3-10 shows the names you may enter at the bootloader prompt.)

When booting the PC, if you enter nothing at the boot loader screen, the bootloader waits for a few seconds and boots the default operating system Thedefault operating system is the one with a check mark in the Default column

in Figure 3-10 In this case, Red Hat Linux is the default operating system.All of the instructions in this section are for your information if you choose

to change any of the default settings You can essentially accept the defaultselections on this screen and click the Next button to proceed to the next con-figuration step

Configuring the Network

If the Linux kernel detects a network card, the Red Hat installation programdisplays the Network Configuration screen (see Figure 3-12), which enablesyou to configure the LAN parameters for your Linux system

This step is not for configuring dial-up networking You need to performthis step if your Linux system is connected to a TCP/IP LAN through an Ethernet card

T I P If the Red Hat installation program does not detect your network card and you have a network card installed on the PC, you should restart the installation and type expert at the boot prompt Then you can manually select your network card

Figure 3-12 The Network Configuration screen enables you to configure the local area

network.

The Network Configuration screen (see Figure 3-12) displays a list of thenetwork card(s) installed on your system and detected by the Linux kernel.The network cards are labeled eth0, eth1, and so on If your system has onlyone Ethernet card, you see only eth0 Figure 3-12 shows that only one net-work card has been detected The default selections for the network card areActive on Boot and Configure Using DHCP If you want to enter an IP addressmanually for your network card or disable the card on boot, click the Edit but-ton to open the Edit Interface dialog box

To disable DHCP remove the check mark from the box and enter an IPaddress and net mask into the appropriate boxes To enable DHCP, click theoption to place the check mark there

To disable the card on boot, remove the check mark from the box To enablethe card on boot, click the option to place the check mark there Normally, youwould want your primary Ethernet interface to be configured on system boot

The Hostname section of the Network Configuration screen shown in Figure3-12 lets you choose how your system hostname will be set The choices are:

■■ Automatically via DHCP— This is the default setting Your PC willobtain its IP address and other network information from a DHCPserver

■■ Manually— If you choose this option, you must provide a hostname.Select DHCP only if a DHCP server is running on your local area network Ifyou choose DHCP, your network configuration is set automatically and youcan skip the rest of this section You should leave the Activate on Boot buttonselected so that the network is configured whenever you boot the system

If you have disabled DHCP, you will need to enter the IP address and netmask manually for the network card by editing the card In addition, you have

to enter certain parameters for the TCP/IP configuration in the text input fieldsfor hostname and the “Miscellaneous Settings” section shown in Figure 3-12.The Network Configuration screen asks for the following key parameters:

■■ The hostname of your Linux system (for a private LAN, you can assignyour own hostname without worrying about conflicting with any otherexisting systems on the Internet)

■■ IP address of the gateway (the system through which you might go toany outside network)

■■ IP address of the primary name server

■■ IP address of a secondary name server (if available)

■■ IP address of a ternary name server (if available)

C R O S S - R E F E R E N C E If you have a private LAN (one that is not directly connected to the Internet), you may use an IP address from a range designated for private use Common IP addresses for private LANs are the addresses in the range 192.168.1.1 through 192.168.1.254 Chapter 11 provides more in-depth information about TCP/IP networking and IP addresses.

After you enter the requested parameters, click Next to proceed to the nextconfiguration step

Configuring the Firewall

In this part of the installation process, you can choose the firewall settings foryour system security Look at Figure 3-13 as you go through this section’s con-figuration steps

Figure 3-13 The Firewall Configuration screen lets you choose your security level.

C R O S S - R E F E R E N C E See Chapter 34 for more information about configuring a firewall.

The first choice that you make from this dialog box is whether you want toenable the firewall or to choose no firewall By default, the installation programselects to enable the firewall for you If you choose to enable the firewall, onlyconnections that are in response to outbound requests are accepted You canalso select individual services that are allowed through the firewall You canallow the following services:

■■ Remote Login (SSH)— If you allow remote access to your serverthrough the SSH protocol, you should enable this option

■■ Web Server (HTTP, HTTPS)— If you plan to run a Web server, youshould choose this option You do not need to choose this option touse a browser to view Web sites

■■ File Transfer (FTP)— If you plan to run an FTP server, you shouldenable this option You do not need to choose this option to retrievefiles from FTP sites

■■ Mail Server (SMTP)— If you are going to run an email server, youshould enable this option You do not need to enable this option toretrieve mail from an ISP.

If you choose the No Firewall option, all connections are allowed and nosecurity checking is done on your system Select No Firewall only if you haveabsolute faith in the security of your network

T I P Choosing to enable the firewall is always safest, especially if you will be connecting directly to the Internet.

The final configuration step on the Firewall Configuration dialog box cerns Security-Enhanced Linux (SELinux) SELinux was developed by theNational Security Agency (NSA) to provide enhanced security based on accesscontrol specified by a security policy You can choose one of three states forSELinux:

con-■■ Disable— If you select this option, SELinux is not enabled on your tem and there is no enforcement of a security policy

sys-■■ Warn— Choosing this option puts a security policy in place, but thepolicy is not enforced Only warnings about possible security violationsare noted If you plan to use SELinux, this option provides a good basisfor determining how the security policy would affect the operation ofyour system

■■ Active— This state applies full enforcement of the SELinux securitypolicy You should choose this option only if you are sure that the policywill not affect your system operation

C R O S S - R E F E R E N C E See Chapter 33 for more information about SELinux.

T I P You can read more about SELinux by visiting the NSA Web site at

www.nsa.gov/selinux.

After you make your configuration choices, click Next to continue

Choosing Additional Languages

The Additional Language Support screen, shown in Figure 3-14 is where youselect the default language to be used on your system

Figure 3-14 On the Additional Language Support screen you set the default language for

your system as well as additional languages you may use.

The language you chose to use for system installation earlier in the tion process will be shown as the default language If you desire to use otherlanguages as well, you can select them from the list Select as many other lan-guages as you desire Note that installing additional languages consumes stor-age space on your disk, so install only the languages you plan to use After youmake your selections, click Next to continue

installa-Setting the Time Zone

After completing the default and additional language selection, you have to

select the time zone — the difference between your local time and Greenwich

Mean Time (GMT) or UTC (the current time in Greenwich, England), which was

selected by the International Telecommunication Union (ITU) as a standardabbreviation for Coordinated Universal Time If you had systems in many dif-ferent time zones, you might want to choose UTC for all your locations to keepyour time synchronized on all your systems The installation program showsyou the Time Zone Selection screen (see Figure 3-15) from which you can selectthe time zone, either in terms of a geographic location or as an offset from UTC.Figure 3-16 shows the selection of a time zone

Figure 3-15 Select your time zone using the Time Zone Selection screen.

Notice that there are two tabs on the Time Zone Selection screen: Locationand UTC Offset Initially, the screen shows the Location tab, which enablesyou to pick a time zone by simply clicking your geographic location As youmove the mouse over the map, the currently selected location’s name appears

in a text field If you want, you can also select your location from a long list ofcountries and regions If you live on the east coast of the United States, forexample, select USA/Eastern Of course, the easiest way is to simply click theeastern United States on the map

If the world view of the map is too large for you to select your location, clickthe View button on top of the map A drop-down list of views appears withseveral choices Click the appropriate view for your location

The other way to set a time zone is to specify the time difference between yourlocal time and UTC Click the UTC Offset tab to select the time zone this way.For example, if you live in the eastern part of the United States, select UTC-05:00 as the time zone The -05:00 indicates that the eastern part of the U.S isfive hours behind UTC time This tab also lets you activate Daylight SavingsTime After you select your time zone, click the Next button to proceed to thenext configuration step

Setting the Root Password

After selecting the time zone, the installation program displays the Set RootPassword screen (see Figure 3-16) in which you set the root password

The root user is the superuser in Linux Because the superuser can do

any-thing in the system, you should assign a password that only you can remember,and that others cannot guess easily Typically, make the password at least eightcharacters long, include a mix of letters and numbers, and (for good measure)throw in some special characters such as + or * Remember that the password

is case-sensitive

Type the password on the first line, and then reenter the password on thenext line Each character in the password appears as an asterisk (*) on thescreen for security reasons Both entries must match before the installationprogram accepts the password The installation program displays a messagewhen it accepts the root password

N OT E You must enter the root password before you can proceed with the rest

of the installation After you do so, click Next to continue with the installation.

Figure 3-16 Setting the root password.

Selecting the Package Groups to Install

After you complete the key configuration steps, the installation program plays a screen from which you can select the Red Hat Linux package groupsthat you want to install After you select the package groups and click Next,take a coffee break while the Red Hat installation program formats the diskpartitions and copies all selected files to those partitions

dis-N OT E If you selected custom installation as your install type, you will see the screen shown in Figure 3-18 If you chose any other installation type, you will see a screen listing the most commonly installed packages for the installation type you chose You can accept the default on that page or you can select Customize software packages to be installed option to pick your own packages, which will then show you the screen in Figure 3-17.

C R O S S - R E F E R E N C E Red Hat uses special files called packages to bundle

files that make up specific software For example, all configuration files, documentation, and binary files for the Perl programming language come in a

Red Hat package You use a special program called Red Hat Package Manager

(RPM)to install, uninstall, and get information about packages Chapter 30 shows you how to use RPM For now, just remember that a package group is made up of several Red Hat packages.

Figure 3-17 shows the Package Group Selection screen with the list of age groups that you can elect to install An icon, a descriptive label, and a radiobutton for enabling or disabling identify each package group

pack-Some of the components are already selected, as indicated by the checkedboxes This is the minimal set of packages that Red Hat recommends for instal-lation for the class of installation (Personal Desktop, Workstation, Server, orCustom) you have chosen You can, however, install any or all of the compo-nents Scroll up and down the list and click the mouse on an entry to select ordeselect that package group

T I P In an actual Red Hat Linux installation, you install exactly those package groups that you need Each package group requires specific packages to run The Red Hat installation program automatically checks for any package dependencies and shows you a list of packages that are required but that you have not selected In this case, you should install the required packages Install only those packages that you think you will need immediately after starting the system Installing too many packages could expose your system to security risks You can always add packages later.

Figure 3-17 GUI screen from which you select the components to install.

Because each package group is a collection of many different Red Hat ages, the installation program also gives you the option of selecting individualpackages If you click the Customize software packages option, which appears

pack-on the Perspack-onal Desktop, Workstatipack-on, and Server package screens and thenclick Next, the installation program takes you to other screens where you canselect individual packages If you are installing Red Hat Enterprise Linux forthe first time, you really do not need to go down to this level of detail to installspecific packages

Notice to the right of each group name there are two numbers separated by

a slash For instance, next to the X Window System is 37/41 This means that

37 of the 41 packages in this group have been selected for installation To theright of the numbers is a link labeled Details Clicking this link opens a newscreen that lists the packages that are in the selected group You can select ordeselect packages as desired

After you select the groups you want, click Next to continue with the rest ofthe installation The installation program now presents the About to Installscreen, as shown in Figure 3-18 This screen tells you which disks are requiredfor the installation

Figure 3-18 The About to Install screen gives you one last chance to cancel the installation

process.

If you are absolutely sure that everything is correct and you are ready toproceed, click Continue to begin the installation The time required for instal-lation depends on the number of packages you chose to install This would be

a good time to take a break, but remember to check the installation’s progressoccasionally as you will need to change CDs A screen showing the installationprogress is displayed to show you how the installation is proceeding

C R O S S - R E F E R E N C E You can always install additional packages later with the RPM utility program, described in Chapter 30.

Running Firstboot

After the installation process completes, you are prompted to remove all disksand to reboot your system A program called Firstboot runs the first time thesystem boots after the installation, as shown in Figure 3-19

Figure 3-19 The Firstboot program runs to let you do additional system configuration.

Shown on the left side of the Firstboot Welcome screen are the steps youmust complete to boot into your newly installed system Proceed as follows:

1 Click Next to continue to the License Agreement screen, as shown inFigure 3-20

Figure 3-20 The License Agreement screen.

2 Click the radio button in front of Yes to accept the License Agreement.

3 Click Next to continue to the Date and Time screen, as shown inFigure 3-21

Figure 3-21 You can verify or change the system time on this screen.

4 Click Next to continue to the Display screen, as shown in Figure 3-22.

Figure 3-22 The Display screen is where you can configure your screen resolution and

color depth.