Two-Minute Drill

Here are some of the key points from the certification objectives in Chapter 1.

Basic Hardware Knowledge

❑	The Red Hat exams are given on computers built for an Intel-based 32-bit architecture.
❑	An Intel-architecture PC has three basic communications channels: IRQ ports, I/O addresses, and DMA channels.
❑	The latest version of Red Hat Enterprise Linux as certified should have at least 256MB of RAM.
❑	You can set up Linux on IDE, SCSI, USB, or IEEE 1394 hard drives. However, the BIOS of a PC can load Linux boot files only from the first two PATA, SATA, or SCSI drives.

Basic Linux Knowledge

❑	Linux is managed through a series of text configuration files.
❑	Understanding text editors is a critical skill. If you ever have to recover your system with a rescue CD, you may not have access to the GUI and will need to know how to use a console-based text editor such as vi.

Linux Filesystem Hierarchy and Structure

❑	Linux directories are organized to the Filesystem Hierarchy Standard (FHS).
❑	In the FHS, devices such as mice and hard drives are grouped in the /dev directory. Some /dev files have logical names such as dvdwriter and are linked to the actual device files.
❑	FHS partitions can be managed and formatted with the fdisk, fsck, and mkfs commands.
❑	The Logical Volume Manager allows you to consolidate multiple partitions in one filesystem, on one directory.
❑	Once configured, Linux directories can be mounted on a partition through /etc/fstab or directly with the mount command.

Basic File Operations and Manipulation

❑	Linux administrators need to know how to use the command line interface.
❑	Basic commands allow you to navigate, find the files that you need, read file contents, create new files, and more.
❑	File filters allow you to search through the files themselves for specific citations or other file characteristics.
❑	Administrative commands allow you to manage Linux in a number of ways, including running processes and managing logged-in users.

Printing

❑	The default Red Hat Enterprise Linux print system is CUPS.
❑	You can configure printers by directly editing the files in the /etc/cups directory or by opening the Red Hat Printer Configuration tool with the system-config-printer command.

Shells

❑	Command lines are based on a shell.
❑	With the right permissions, you can set up shell programs in executable scripts.
❑	The way a shell works depends on the settings in its variables and parameters. Some variables and parameters are grouped in the inherited environment, which maintains settings from shell to shell.
❑	With stdin, stdout, and stderr, you can manage different data streams.

Basic Security

❑	Basic security within Linux is based on file permissions, users, groups, and umask.
❑	The SUID and SGID bits allow you to share owner-level permissions with different users and groups.
❑	Shadow passwords hide user authentication data. The Shadow Password Suite protects user and group passwords in files that should be accessible only to the root user.

System Administration

❑	While it's normally best to log in as a regular user, it's faster to log in as the root user for the RHCE and RHCT exams.
❑	Standard files for new users are kept in /etc/skel.
❑	Daemons are processes that run in the background.
❑	Network service can be controlled through scripts in the /etc/init.d and /etc/ xinetd.d directories.
❑	The cron daemon helps you schedule different jobs, including backup and restore jobs, which should be done when network use is at a minimum.
❑	When you have problems, system log files, as organized by /etc/syslog.conf, provide important clues to the causes.

Basic TCP/IP Networking

❑	Most of the work in TCP/IP networking is in configuring IP addresses.
❑	There are three different sets of private IPv4 addresses suitable for setting up TCP/IP on a LAN.
❑	IPv6 addresses include all available IPv4 addresses. If the first three bits of an IPv6 address are 001, that is a unicast address-in other words, one that is associated with a specific computer or other device.
❑	The first 48 bits of an IPv6 address are typically associated with a specific network.
❑	Tools such as ping, ping6, ifconfig, and netstat can help you diagnose problems on that LAN.
❑	Name resolution configuration files determine how your computer finds the right IP address.

Familiarity with Standard Network Services

❑	There are a number of standard network services, including NFS, sendmail, POP, IMAP, FTP, DNS, DHCP, Samba, Apache, and NIS.
❑	Each of these services, when installed, can be configured to start and stop through the scripts located in the /etc/rc.d/init.d or /etc/xinetd.d directories.

Basic Network Security

❑	Basic network security settings can depend on allowing or denying access to different computers by their IP addresses or by the desired TCP/IP port.
❑	Computers behind a firewall can be protected through Network Address Translation or various iptables commands.

Other Basic Prerequisite Skills per the Red Hat Exam Prep Guide

❑	While GUI e-mail clients should be trivial, it's important to know how to configure a command line e-mail client.
❑	While GUI Web browsers should be trivial for serious Red Hat exam candidates, it can help to know a text-based browser such as elinks.
❑	While GUI FTP clients should be trivial for serious Red Hat exam candidates, it can help to understand a text-based FTP client such as lftp.

Downloading the Red Hat Enterprise Linux Installation CDs

❑	There is no evidence that you need to know how to download the Red Hat installation CDs for the Red Hat exams.
❑	While the best option is to download the RHEL 5 CDs from the Red Hat Network, excellent options are available.
❑	You can use the rebuild distributions to prepare for the Red Hat exams. Their distributions are built on the same source code used by Red Hat for RHEL 5.