Chapter 8 - Configuring Networks Flashcards
What are the two types of IP addresses available now?
IPv4 and IPv6
What is an IPv4 address?
These are based on 32-bit addresses and have four octets, separated by dots, such as 192.168.10.100.
What is an IPv6 address?
These are based on 128-bit addresses and are written in eight groups of hexadecimal numbers that are 16 bits each and separated by colons.
An IPv6 address may look like fe80:badb:abe01:45bc:34ad:1313:6723:8798.
What is a host?
A host is typically a server providing services on the network
How does computers commuinicate?
To make it easier for computers to communicate with one another, every IP address
belongs to a specific network, and to communicate with computers on another network,
a router is used
What is a router?
A router is a machine (often dedicated hardware that has been created for that purpose) that connects networks to one another.
What are private IP addresses?
Private network addresses are addresses that are for use in internal networks only. Some specific IP network addresses have been reserved for this purpose:
- 10.0.0.0/8 (a single Class A network)
- 172.16.0.0/12 (16 Class B networks)
- 192.168.0.0/16 (256 Class C networks)
What is the length of MAC addresses?
12-byte MAC address
An example of a MAC address is 00:0c:29:7d:9b:17.
What are the two parts of the MAC addresses?
The first 6 bytes is the vendor ID, and the second 6 bytes is the unique node ID
How do the default names of network cards in RHEL8 begin?
- Ethernet interfaces begin with en, WLAN interfaces begin with wl, and WWAN interfaces begin with ww.
- The next part of the name represents the type of adapter.
- Then follows a number, which is used to represent an index, ID, or port
- If the fixed name cannot be determined, traditional names such as eth0 are used.
Which command or utility can be used to check the configuration of network?
ip utility, or the ip command
what is the command “ip addr” used for?
Use ip addr to configure and monitor network addresses
What is the command “ip route” used for?
To configure and monitor routing information
Which command is used to configure and monitor network link state?
ip link
Which command to use to check or show current network settings?
ip addr show
Which interface is used for communication between the processes and what is the default IP of the loopback interface in Linux?
The loopback interface is used for communication between processes. Some processes are using the IP protocol for internal communications. For that reason, you’ll always find a loopback interface, and the IP address of the loopback interface is always set
to 127.0.0.1
What are all the informations seen in “ip addr show” command?
- Current state
- MAC address Configuration
- IPv4 configuration
- IPv6 Configuration
Which command to use if you are just interested to see the link status of the network interfaces?
ip link show
Which service in RHEL8 manages the networking?
NetworkManager service.
You can use the systemctl status NetworkManager
command to verify its current status
For what purpose is the commands nmtui command or the nmcli command used for?
To manage the network connections that you want to assign to devices, you use the nmtui command or the
nmcli command.
Which command to use to check your current permissions with changing/modifying the network configuration?
nmcli gen permissions
Which command can be used to temporarily set IP address on a network interface?
ip addr add
How to use nmcli command to show all connections?
nmcli con show
This shows active and inactive connections. You can easily see the difference because inactive connections are not currently assigned to a device
How to see all the properties of the network interface ens33?
nmcli con show ens33
syntax is : nmcli con show
What is the difference between a connection and a device?
A device is a network interface card.
A connection is the configuration that is used on a device.
nmcli con show
nmcli dev status
What command is a text user interface that allows you to create network connections easily?
nmtui
How to use the nmcli command to modify an existing setting?
nmcli con mod
What are the menu options in nmtui interface?
- Edit a Connection
- Activate a Connection
- Set System Hostname
Every network connection that you create is stored in a network configuration file. Where is this file present?
/etc/sysconfig/network-scripts
How to identify the names of network configuration files?
The name of the configuration files starts with ifcfg- and is followed by the name of the network interface.
Why is hostname necessary?
To communicate with the other hosts. Makes it more readable than IP addresses.
What are the different parts in a hostname?
Hostname typically consists of different parts. These are the name of the host and the DNS domain in which the host resides.
These two parts together make up for the fully qualified domain name (FQDN), which looks like server1.example.com
What is FQDN?
Fully qualified domain name (FQDN) It is the name of the host and the DNS domain in which the host resides all together
What are the different ways to change the hostname in linux?
- Use nmtui and select the option Change Hostname.
- Use hostnamectl set-hostname command
- Edit the contents of the configuration file /etc/hostname.
Give an example of setting hostname using hostnamectl command?
hostnamectl set-hostname myhost.example.com
Which command to use to check the current hostname?
hostnamectl status
What are the two columns in /etc/hosts file?
The first column has the IP address of the specific host, and the second column specifies the hostname.
In which configuration file is the DNS information stored in ?
The NetworkManager configuration stores the DNS information in the configuration file for the network connection, which is in /etc/sysconfig/network-scripts, and from there pushes the configuration to the /etc/resolv.conf file, which is used for DNS name server resolving.
Do not edit /etc/resolv.conf directly, as it will be overwritten the next time you restart NetworkManager.
What are the different ways to set the DNS server?
- Use nmtui to set the DNS name servers.
- Set the DNS1 and DNS2 parameters in the ifcfg network connection
configuration file in /etc/sysconfig/network-scripts. - Use a DHCP server that is configured to hand out the address of the
DNS name server - Use nmcli con mod [+]ipv4.dns.dns
if your computer is configured to get the network configuration from a DHCP server, the DNS server is also set via the DHCP server. If you do not want this to happen what should you do?
]1. Edit the ifcfg configuration file to include the option PEERDNS=no.
or
2. Use nmcli con mod ipv4.ignore-auto-dns yes.
