ICT

Types of DNS server

len Alfred Ajibola -11th June, 2019 @ 5:58 PM

Topics in ICT

Introduction to routers in networking Wired router and wireless router explained What are core routers in networking? Virtual routers explained with its configuration Edge router explained with its types Domain Name System explained Types of computer network Functions of a router Computer scheme of work, SS1, First Term Computer scheme of work, SS1, Second Term Computer scheme of work, SS1, Third Term Introduction to computer networks Types of DNS server Open Systems Interconnect: Layers of the OSI Model Internet of Things (IoT), How IoT works, its advantages and challenges How to consume less data on android phone Best programming languages to learn The internet and world wide web explained Computer Hardware, Parts and Functions of Computer Hardware


Academic Questions in ICT

Please click here to see all Questions and Answers

What is the first step towards disabling automatic image download on WhatsApp?

  • A. Click on the three dots on the top right hand corner

  • B. Click on the WhatsApp logo

  • C. Click on the settings icon on the top right corner

  • D. Click on the settings icon located on the to top-center of the app

  • E. Click directly on the storage and data icon located on the top right corner

  • F. Click on the mobile data usage icon located on the top right corner

The followings are ways to conserve data on android phones except _____.

  • A. Turning on data saving mode

  • B. Activating background apps

  • C. Use of Wi-Fi to update apps

  • D. Disable automatic image download on WhatsApp

  • E. Watch low resolution videos on youtube

  • F. Utilizing a reputable data saving app on google playstore

Twitter was launched in _____.

  • A. 2003

  • B. 2004

  • C. 2005

  • D. 2006

  • E. 2007

  • F. 2008

Due to the limitation of the Internet Protocol version 4 address, _____ was created.

  • A. IPv5

  • B. IPv6

  • C. IPv7

  • D. IPv8

  • E. IPv9

  • F. IPv10

The term _____ describes the billions of physical devices that will be connected to the internet.

  • A. Internet of Everything

  • B. Internet of Physical Devices

  • C. Internet of Things

  • D. Internet of Objects

  • E. Internetworking

  • F. Internetworking of Objects

A globally interconnected network system that utilizes TCP and IP to transmit data via various media is the _____.

  • A. World Wide Web (www)

  • B. Http

  • C. Https

  • D. Https://www

  • E. LAN

  • F. Internet

Power Supply Unit - Len Academy

The above image shows the _____ in a computer.

  • A. Expansion slot

  • B. Hard Disc Drive

  • C. Optical Drive

  • D. Power Supply Unit

  • E. Motherboard

  • F. Synchronous Dynamic Ram

The clock speed of a computer is the speed at which the _____.

  • A. HDD saves data

  • B. FDS saves data

  • C. SSD saves data

  • D. GPU receives and sends data

  • E. CPU processes data

  • F. RAM transfers data


What is Domain Name System?

Domain Name System (DNS) is a layer seven protocol or application layer protocol of the OSI model of networking. With regards to the TCP IP stack, it is also an application layer protocol.

You can read on the OSI model of Networking here.


Functionally, DNS maps domain names to IP addresses. In simple terms, you can think of it as a phone book that correlates website names to their respective IP address. As an instance, this website (len.com.ng) is actually an IP address. Through the help of DNS, you do not need to memorize the IP address of len.com.ng. Meanwhile, understand that it is much easier to memorize the names of websites rather than their respective IP addresses.

Please the concept of DNS and how it works here.


Types of DNS Server

DNS servers are classified into four types. These are:


1. DNS Recursor: The function of the recursive DNS server is to receive DNS queries directly from your computer or phone or any other client machine that has a browser.

The DNS recursor then makes additional request so that the correct IP address can be given back to the client machine.

  • If the recursive DNS server had already cached the correct IP address for the domain name (probably from an initial request), there will be no need for it to send an additional request to another DNS server (termed the Root Nameserver). Instead, it directly sends the correct IP address to the client machine.

Please read on routers here.


2. Root Nameserver: This is the first DNS server that translates domain names into IP address. It does not contain a list of all the IP addresses for every domain name.

The root Nameserver only serves the domain name for specific locations.


3. Top Level Domain (TLD) Nameserver: This name server hosts the last segment of a domain name. As an instance, in the domain name (example.com), the TLD server hosts the '.com' portion of such name.

You can read on notable dates of internet evolution here.


4. Authoritative Nameserver: Think of it as an encyclopedia that contains all domain names with each name mapped specifically to its correct IP address.

The authoritative name server returns the IP address to a specific domain name if it has the records, else the intended website (domain name) will be unreachable.

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Amazing facts in ICT

YouTube is a video-sharing platform which commenced operations on February 14, 2005 (Valentine's day). Three former PayPal employees -> Chad Hurley, Steve Chen and Jawed Karim created the YouTube service (as a dating app) until Google bought it in November 2006 for US$1.65 billion

Smoking near a Mac device - Len Academy

Smoking near an Apple (Mac) computer voids the warranty.

When you add /4 to the end of Facebook's URL, it will take you to Mark Zuckerberg.

You can try it on you own; or better still, try the link below:

facebook.com/4

Apple iPad retina - Len Academy

Apple iPad retina display is actually manufactured by Samsung

The big five tech companies of the world as at 2018 are :

Google

Apple

Facebook

Amazon

Microsoft


NOTABLE POINTS IN ICT

Computer hardware is the collection of physical parts of a computer system.

Physical parts of a computer are those parts that you can see and touch. It may also be referred to as the 'equipment of the computer'.

When the computer case is opened (with a screwdriver), one would see the different hardware components inside of it. It's important to state that some other hardware components are present outside the computer case; and these are termed peripherals.

Below are hardware components seen inside the computer case:

  • Motherboard

  • Central Processing Unit (CPU)

  • Graphics Processing Unit (GPU)

  • Power supply Unit (PSU)

  • Northbridge

  • Southbridge

  • Peripheral Component Interconnect (PCI) slots

  • Network Interface Card (NIC)

  • Random Access Memory (RAM)

  • Ventilation fans

  • Heat sink

  • Hard Disc Drive (external present)
  • Solid State Drive (SSD)

  • CMOS battery

  • Optical Disc Drives (external present)

  • USB port, PS2 port, Ethernet port and other ports

  • Expansion Ports / Slots

Please read more on computer hardware here

Hardware components seen outside the computer case are called peripherals. The peripherals are grouped into the following:

  1. Input devices: They provide information to the computer.

  2. Output devices: Brings out information from the computer.

  3. Storage devices: They store information or data.

Below are examples of some peripherals:

  • Keyboard (input)

  • Monitor (output)

  • Mouse (input)

  • Webcam (input)

  • Touch Pad (input)

  • Universal Serial Bus (USB) flash drive or memory card (storage)

  • Hard disc drive (storage)

  • Stylus (input)

  • Joystick(input)

  • Printer (output)

  • Speaker (output)

  • Headphones (output)

Computer Network is a group of computers that are linked to each other such that they can share resources.

Generally, these groups of computers that form a network are called nodes.

Some of these nodes will function to store information which will be served to other computers. The nodes that function to store and serve such information are known as servers.

Some of the computers (nodes) will request information from the server. The computers that functions to request information from the server are known as clients.

Please read on computer networks here

The internet and the world wide web (www) isn't the same thing.

The internet is formed from the joining or linking of different networks.

For instance, Google's network, Facebook's network and Yahoo's network are among the many other networks that make up the internet.

World Wide Web on the other hand is a collection of linked pages (for instance, this page you're on).

There are actually billions of linked pages in various servers around the world.

You require the internet and a web browser to get to access the World Wide Web

Please read more on the internet here

Types of Networks based on geographical size

  1. Personal Area Network (PAN): An instance is a Bluetooth connection between two devices.

  2. Local Area Network (LAN): This is the network under a single administrative control and usually within a building.

  3. Campus Area Network (CAN): This network connects various devices within a campus or college

  4. Metropolitan Area Network (MAN): This network connects two offices or companies within a city.

  5. Wide Area Network (WAN): This network connects devices throughout the globe. The internet is a typical example of a WAN.

You can read more on the types of network based on geographical size here