Understanding Different Networking Concepts
A network consists of computers and other electronic devices that are connected to each other over a transmission medium. The transmission medium can be cable (copper or optical fibre), Wi-Fi, radio waves, infrared waves, or a satellite.
There are many benefits of computer networks such as higher speed, reduced cost, enhanced security, flexible access, email access, and centralised software and hardware management.
A network allows users to share both software and hardware such as printers, scanners, and applications. Each device on the network is referred to as a node, and each node has a unique network address. Some computer networks also have a server that is used to manage various networking resources. A server is a computer that functions as a central repository for storing files and running programs centrally. It processes requests and sends data to other computers (clients) over a local network or the Internet.
Identifying Different Types of Networks
There are many types of computer networks that are characterised on the basis of size or purpose. The size of a network is expressed depending on the geographical area it occupies and the number of computers that are a part of the network. The size of a network can vary from a few computers in a room to millions of computers spread across the globe.
On the basis of size, networks are classified under the following categories:
Local Area Network (LAN)
It is a network that is confined to a small geographical area such as a school, office, or multiple offices within a campus. However, a single LAN can be connected to other LANs over long distance via telephone lines and radio waves. The LAN is a private network which can restrict communication to the nodes within the network and prevent it from reaching the Internet.
Metropolitan Area Network (MAN)
MAN is a large, high-speed computer network that usually spans a large campus or an entire city. A MAN usually interconnects multiple LANs using high-capacity fibre-optical links. MAN covers the geographical area larger than the LAN but smaller than the area covered by a WAN (Figure 3). Companies that use MAN usually have several branches within a city such as banks, local ISPs, cable television companies and local telephone companies. Metro Ethernet is one of the latest forms of MAN.
Wide Area Network (WAN)
It is a network that spans over a large geographical area, such as a country or the entire world. A WAN can contain multiple smaller networks, such as LANs and MANS. WANs are used by large organisations to interconnect LANs at offices in different countries. The Internet is the biggest public WAN and a network of ATMs is a private WAN.
Virtual Private Network (VPN)
It is a type of network that allows computers or an entire network to connect to each other over the Internet securely. VPN is based on the client-server architecture so it consists of a VPN client and VPN server and the software that enables secure connections. VPN uses different security tools such as tunneling protocol. The tunneling protocol creates a tunnel between two devices and encrypts all the information in the tunnel.
VPNs are mostly used by organisations to protect sensitive data. They use tunneling protocols such as Point-To-Point Tunneling (PPTP) and Secure Socket Layer (SSL) for secure authentication and encryption of the network traffic.
Wired and Wireless Network
Communication Over a network can either be wired or wireless depending on the medium. A wired network connects devices to the Internet or other networks using cables, whereas a wireless network connects devices using wireless technologies such as infrared and radio waves. Transmission medium is one of the most important components of any communication/computer network. The transmission medium carries information from the sender to the receiver, and make Internet access possible. Different transmission media have different properties like bandwidth, delay, cost, ease of installation and maintenance. Transmission media are broadly classified into two types:
Wired: This network uses physical cables and is limited in geography. LAN is a wired orb. Ethernet is the most commonly technology for setting up LANs. A LAN can be configured a single router and a few Ethernet cables. A standard Ethernet Cable’s slightly thicker than a traditional telephone cable and has an RJ-45 connector filtered on each end.
Wireless: This network uses, radio waves and infrared waves that are not restricted by geography. Wireless connectivity (popularly known as Wi-Fi) allows devices to connect to the Internet without using a physical wired connection. Wi-Fi enabled devices use radio waves to communicate with other devices. Wi-Fi is a type of WLAN that follows IEEE 802.11 standards.
When you connect your laptop or smartphone to a Wi-Fi hotspot at a hotel, airport lounge or other public place, you’re connecting to a wireless network.
Table 1 shows the most commonly used wireless networks:
|Wireless Local Area Network
|Within a home, school or office.
|IEEE 802.11, Wi-Fi, and HiperLAN
|Within a city||High||Proprietary, IEEE 802.16, and WIMAX
|WWAN||Wireless Wide Area Network
|Worldwide||Low||CDPD and Cellular 2G, 2.5G, and 3G
|WPAN||Wireless Personal Area Network||Within reach in person||Moderate||Bluetooth, IEEE 802.15
Home Area Network (HAN)
HAN is a network that connects all devices in your home to the Internet and to each other. These devices include desktop computer, laptop, mobile phone, tablet, printer and gaming system. You can set up a home network to perform the following tasks:
- Share an Internet connection between connected devices
- Access data on all devices connected to the network
- Print from any device connected to the network
- Centrally manage network security settings for connected devices
Setting Up a Wireless Network
Setting up a wireless network is an easy and straightforward process if you have the required hardware in place. Before setting up your wireless network, you must have a broadband Internet connection, modem, wireless router and a wireless network adapter.
Broadband Internet connection and modem: A broadband Internet connection is a high-speed Internet connection. You can contact your Internet Service Provider (ISP) to get a broadband Internet connection. Typically, ISPs that provide DSL connections are telephone companies. ISPs frequently offer broadband modems. Some ISPs also offer combination modems/wireless routers.
Wireless router: A router sends data from one network to another or the Internet either wired or wirelessly. With a wireless router, you can connect your computer to the network wirelessly using radio signals instead of cables.
Wireless network adapter: A wireless network adapter is a device that connects your computer to a wireless network. Nowadays, most PCs come with a built-in wireless network adapter.
Wireless Network Security Threats and Control Measures
Like any other technology, wireless network technology has its own share of vulnerabilities. Unlike wired networks, wireless networks do not have built-in physical security. Therefore, they are more prone to attacks. It is important to understand the threats to wireless networks to be able to guard against them.
Threats to Wireless Networks
Nowadays, wireless LANs are present almost everywhere. With an increase in the proliferation of wireless networks, the number of threats has also significantly increased. The main reason for this is that an attacker does not need physical access to the network and can intrude from a distance. The threats related to wireless network security are as follows:
Misconfiguration: Many novice users deploy their wireless networks on their own using default unsecured configurations. This makes it possible for hackers to gain easy access to their networks, hard drives and use resources such as Internet connections. To correctly configure your wireless router, you must always read the instructions manual that came with it.
Evil Twin: An evil twin is a (rogue) wireless network access point that impersonates as a legitimate wireless access point. Hackers create evil twins to trick users looking for free Internet connections. The evil twin looks like a hot spot with a very strong signal that attracts users to connect to it. Once users log in, they become susceptible to attacks of various kinds.
War Driver: The act of searching for unsecured Wi-Fi networks by an individual in a moving vehicle, using a computer and an 802.11 wireless LAN adapter is called war driving. This is done to gain unauthorized access to computers on the non-secure Wi-Fi network. This attack can be performed by the war driver within the range of the router.
You must configure your wireless network keeping the following tips in mind:
Turn off your wireless network when you’re away from home: This will minimize the possibility of a hacker accessing your network.
Set up a security key for your network: Wireless networks can be protected from unauthorized access with a network security key (or password). A router usually comes with a default user name and password that is used to setup and configure it. Hackers are aware of these login credentials; therefore, it is important to change the default password to something that is difficult to crack. If your router supports Wi-Fi Protected Access 2 (WPA2) security, always keep that setting enabled.
Enable encryption: You can configure your router to allow access only to users who enter the correct password. These passwords are encrypted when they are transmitted. Therefore, when hackers who try to intercept your connection, they will not be able to read your password.
Use a firewall: Firewall provides an extra layer of defence and can significantly reduce the chance of attackers gaining access to your private wireless network. It monitors attempts to access your system and blocks communication from unknown sources. Most operating systems have a built-in firewall that you can configure.
Securing Wi-Fi Networks
It is imperative to secure wireless networks at the time of setup. This is because network users exchange information that is of confidential nature such as credit card details, medical records, and other financial or secret information. This information must be protected from hackers.
Therefore, it is important to know the frequency that will be used by the equipment that is deployed. This helps to control the amount of interference that the network will face in the environment where it is deployed. Secondly, the security protocol that you choose to use (such as WPA2) will be the most important factor in deciding the security of your wireless network.
To secure a wireless network:
- Read the instructions manual and locate the default user name, password and network name for the wireless access point.
- Plug in the router into the electrical socket and ensure that all the lights are blinking.
- Access any web browser and navigate to http://192.168.1.1.
- In the respective fields, enter the default username and password.
- On the Administration page, follow onscreen instructions to change the password.
- Click Save settings.
- Log in to the router providing the username and password that you have just created.
- On the Wireless tab, on the Administration sub-tab, change network name.
- Click Save settings.
- To encrypt a wireless connection, choose the highest level of protection that all computers in a network can handle.
Measures for Securing Network Connections
With advancements in computer technology, there is a proliferation in the number and severity of threats affecting networks. To ensure that your data is safe at all times and your network is protected from hackers, it is mandatory to strengthen your defences. Experts recommend implementation of additional security measures over and above the usual security protocol followed on most networks.
Network connections are further secured if following security measures are in place:
Firewall: It is a software that prevents hackers or malicious software from gaining unauthorized access to your computer through a network. Firewall filters all network traffic, guards against and reports any intrusion attempt on your computer. Your network must have a firewall. Note that a firewall cannot protect a system against new threats, malicious insider and connections that dofge it.
Antivirus: It is a software that is designed to detect and destroy virus on a computer. It safeguards a computer against viruses, trojan horses, malware and malicious programs such as spyware and adware. Most modern antivirus software have an update feature, which enables the software to download virus definitions as and when they are available. The virus definitions enable the antivirus to identify and remove any new threats that were previously unknown to the tool. Norton Antivirus, McAfee, Avast, and AVG are some of the commonly used antivirus software.
Encryption: Encryption is a security technique used to encode the data sent over a network. It makes the data unreadable by converting it to a special type of code. This ensures that only authorized users can read the data after it is decrypted using a key or a password. It is also possible to encrypt an entire network.
Browsing Only Secure Websites: It is a good practice to browse secure websites, especially when you are exchanging personal and sensitive information, for example, while performing a financial transaction. Secure websites use encryption to protect personal information (financial and medical) that you try to send over the Internet.
The following methods can be used to identify a secure website:
- Lock icon: When you see a lock r icon in the address bar it means that the website you are visiting encrypts any information that you enter. The icon also indicates that the web browser has verified the website’s ownership with a certificate and will encrypt the traffic to and from the website.
- URL: In addition to the lock icon, you will see https instead of the usual http as in https://. The ‘s’ in https stands for ‘Secure’ and indicates that all communication between your browser and the website is encrypted. This ensures that the information that you provide on the website is safe and cannot be accessed by hackers. HTTPS uses HTTP with the Secure Sockets Layer (SSL) cryptographic protocol and its successor Transport Layer Security (TLS) protocol.