Glossary

As the Red Hat exams are an advanced challenge, I limit this glossary to what you would see beyond the prerequisites; don't expect to see most basic terms from Chapter 1 here.

A-C

Access Control Lists (ACLs)

Access Control Lists (ACLs) provide an additional layer of access control to files and directories; associated with the setfacl and getfacl commands.

Address Resolution Protocol (ARP)

A protocol that maps an IP address to the hardware address on a network card.

anacron

The anacron service is designed to run cron jobs that could not run while a server was powered down.

Apache Web server

The Apache Web server provides both normal and secure Web services, controlled by the httpd daemon.

apachectl

The apachectl command is the preferred method to start and stop an Apache server.

arp (Address Resolution Protocol)

The arp command is used to view or modify the kernel's ARP table. Using arp, you can detect problems such as duplicate addresses on the network. Alternatively, you can use arp to add the required entries from your LAN.

at

The at command is similar to cron, but it allows you to run a job on a one-time basis.

authentication

The way Linux checks the login rights of a user. Linux and Unix users are normally authenticated through use of a username and password, checked against /etc/passwd and related files.

automounter

The automounter can be configured to mount local and network directories on an as-needed basis. It's configured in /etc/auto.master, /etc/auto.misc, /etc/auto.smb, and /etc/auto.net.

BIND (Berkeley Internet Name Domain)

BIND is the Unix/Linux software that is used to set up a Domain Name System (DNS) service. The associated daemon is named.

BIOS

The BIOS is the Basic Input/Output System that runs basic commands when you power up your computer. The BIOS menu allows you to customize many options, including the sequence of boot media.

/boot

The directory with the main files required to boot Linux, including the Linux kernel and initial RAM disk. By default, /boot is mounted on a separate partition.

BOOTP

A TCP/IP protocol that sends IP address information from a remote DHCP server.

caching-only name server

A caching-only name server that performs many of the functions of a DNS server. It stores the IP address associated with recent name searches, for use by other computers on your LAN.

chage

The chage command manages the expiration date of a password.

chattr

The chattr command allows you to change file attributes.

chgrp

The chgrp command changes the group that owns a file.

chkconfig

The chkconfig command manages runlevel service information. It can activate or deactivate services. It can also customize services at specific runlevels.

chmod

The chmod command changes the permissions on a file.

chown

The chown command changes ownership on a file.

CIFS (Common Internet File System)

CIFS is the Microsoft name for advances in its networking software. It's also covered by the latest version of Samba, 3.0, which is included with RHEL.

client

A client is a computer that accesses information or resources from a server.

CNAME (canonical name)

The CNAME is a way to assign several different names to a computer in a DNS database. For example, you can set up www as an alias for the computer with your Web server. CNAME records cannot be assigned to a mail server (MX) or a Start of Authority (SOA) record.

cron

A service that runs jobs on a periodic basis. It's configured in /etc/crontab; by default, it executes jobs in the /etc/cron.hourly, /etc/cron.daily, /etc/cron.weekly, and /etc/cron.monthly directories.

crontab

Individual users can run the crontab command to configure jobs that are run periodically.

CUPS (Common Unix Printing System)

CUPS is the default print service for RHEL.