Objectives 1.0 Hardware and System Configuration Flashcards
Describe the boot process
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
What is GRUB?
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
What is GRUB2?
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)
lsmod
show a list of statuses of modules in Linux Kernel
insmod
inserts module by path only
no dependencies
fail with no explanation
modprobe
inserts module just by name includes dependencies needs map
modinfo
shows information about a linux kernel module
dmesg
print or control the kernel ring buffer
rmmod
removes a module from the linux kernel
depmod
List modules dependencies and map files
Where are Linux Network Configuration files stored on Redhat?
/etc/sysconfig/network-scripts directory
Where are Linux Network Configuration files stored on openSUSE?
/etc/sysconfig/network
Where are Linux Network Configuration files stored on Debian based?
/etc/network/interfaces file
route
show / manipulates IP routing table
host
host is a simple DNS lookup utility. It is normally used to convert names to ip addresses and vice versa
ping
sends ICMP requests to network hosts. It works with both IPv4 and IPv6. Can be enforced by specifying -4 or -6
dig
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
nslookup
nslookup is a program to query internet domain name servers. Has two modes: interactive and non-interactive
ip
shows/manipulates routing, devices, policy and routing tunnels
ethtool
query or control network driver and hardware settings
/etc/hosts
Before a DNS is queried it comes to this file
What is load balancing?
Network traffic is shared between two or more network interfaces
What is aggregation?
Two or more network interfaces are combined to create one larger network pipe
Active/passing
One network interface is live while the other is used as a backup for fault tolerance
Describe the command-line utilities required to configure and manipulate Ethernet network interfaces
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.
Explain how to configure basic access to a wireless network
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.
Describe how to manipulate the routing table on a Linux system
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
Summarize the tools you would need to analyze the status of network devices
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
Describe how Linux initializes the network interfaces
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
Explain how to test network connectivity
The ping and ping6 commands allow you to send ICMP messages to remote hosts and display the response received
Describe one graphical tool used to configure network settings in Linux
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
