Objectives 1.0 Hardware and System Configuration

Question 1

Describe the boot process

Answer 1

The Linux Boot process can be split into three main steps:

1) The BIOS or UEFI starts a bootloader program from the Master Boot Record, which is usually the Linux GRUB Legacy or GRUB2 program.
2) The bootloader program loads the Linux kernel into memory, which in turn looks for the init program to run.
3) The init program starts individual application programs and starts either the command-line terminals or the graphical desktop manager

Question 2

What is GRUB?

Answer 2

GRUB stands for Grand Unified Bootloader

GRUB stores files in /boot/grub folder and uses the menu.lst or grub.conf configuration file to define commands used at boot time

difficult to modify

boot menu usually displays on boot

Question 3

What is GRUB2?

Answer 3

Stored in /boot/grub

Uses grub.cfg

Customizable in /etc/default/grub

can boot iso, usb, UUID, device

grub2 has a hidden boot menu (press shift)

Question 4

lsmod

Answer 4

show a list of statuses of modules in Linux Kernel

Question 5

insmod

Answer 5

inserts module by path only
no dependencies
fail with no explanation

Question 6

modprobe

Answer 6

inserts module just by name
includes dependencies 
needs map

Question 7

modinfo

Answer 7

shows information about a linux kernel module

Question 8

dmesg

Answer 8

print or control the kernel ring buffer

Question 9

rmmod

Answer 9

removes a module from the linux kernel

Question 10

depmod

Answer 10

List modules dependencies and map files

Question 11

Where are Linux Network Configuration files stored on Redhat?

Answer 11

/etc/sysconfig/network-scripts directory

Question 12

Where are Linux Network Configuration files stored on openSUSE?

Answer 12

/etc/sysconfig/network

Question 13

Where are Linux Network Configuration files stored on Debian based?

Answer 13

/etc/network/interfaces file

Question 14

route

Answer 14

show / manipulates IP routing table

Question 15

host

Answer 15

host is a simple DNS lookup utility. It is normally used to convert names to ip addresses and vice versa

Question 16

ping

Answer 16

sends ICMP requests to network hosts. It works with both IPv4 and IPv6. Can be enforced by specifying -4 or -6

Question 17

dig

Answer 17

dig is a DNS tool for interrogating DNS name servers. It performs DNS lookups and displays the answers that are returned from the name. Use dig to troubleshoot DNS problems

Question 18

nslookup

Answer 18

nslookup is a program to query internet domain name servers. Has two modes: interactive and non-interactive

Question 19

ip

Answer 19

shows/manipulates routing, devices, policy and routing tunnels

Question 20

ethtool

Answer 20

query or control network driver and hardware settings

Question 21

/etc/hosts

Answer 21

Before a DNS is queried it comes to this file

Question 22

What is load balancing?

Answer 22

Network traffic is shared between two or more network interfaces

Question 23

What is aggregation?

Answer 23

Two or more network interfaces are combined to create one larger network pipe

Question 24

Active/passing

Answer 24

One network interface is live while the other is used as a backup for fault tolerance

Question 25

Describe the command-line utilities required to configure and manipulate Ethernet network interfaces

Answer 25

To set the IP and netmask addresses on an Ethernet interface, you use the ifconfig or ip command. To set the default router (or gateway) for a network, you use the route command. Some Linux distributions that have Network Manager installed can use the nmtui or nmcli command, which can configure all three values.

Question 26

Explain how to configure basic access to a wireless network

Answer 26

Linux uses the iwlist command to list all wireless access points detected by the wireless network card. You can configure the settings required to connect to a specific wireless network using the iwconfig command. At a minimum, you’ll need to configure the access point SSID value and most likely specify the encryption key value to connect to the access point.

Question 27

Describe how to manipulate the routing table on a Linux system

Answer 27

The route command displays the existing router table used by the Linux system. You can add a new route by using the add option or remove an existing route by using the del option. You can specify the default router (gateway) used by the network by adding the default keyword to the command

Question 28

Summarize the tools you would need to analyze the status of network devices

Answer 28

The ifconfig and ip commands display the current status of all network interfaces on the system. You can also use the netstat or ss commands to display statistics for all listening network ports

Question 29

Describe how Linux initializes the network interfaces

Answer 29

Debian-based Linux systems use the /etc/network/interfaces file to configure the IP address, netmask, and default router. Red Hat–based Linux systems use files in the /etc/sysconfig/network-scripts folder. The ifcfg-emp0s3 file contains the IP address and netmask settings, while the network file contains the default router settings. These files are examined at bootup to determine the network interface configuration. Newer versions of Ubuntu use the Netplan tool, which stores the network configuration in the /etc/netplan folder

Question 30

Explain how to test network connectivity

Answer 30

The ping and ping6 commands allow you to send ICMP messages to remote hosts and display the response received

Question 31

Describe one graphical tool used to configure network settings in Linux

Answer 31

The Network Manager tool provides a graphical interface for changing settings on the network interfaces. The Network Manager appears as an icon in the desktop system tray area. If your Linux system uses a wireless network card, the icon appears as a radio signal, while for wired network connections it appears as a mini-network. When you click the icon, it shows the current network status, and for wireless interfaces, it shows a list of the access points detected. When you open the Network Manager interface, it allows you to either set static IP address information or configure the network to use a DHCP server to dynamically set the network configuration