Types of Firewall

Firewall is a first line of defense and protective barrier between your network and the outer world. It can be a software or hardware and it is configured and attached with the gateway computer. It encrypts, filters, monitors, permits or denies all the network traffic. A system without the implementation of the firewall can easily be attacked by the viruses, hackers, intruders, unauthorized access and other internal and external threats. It regulates the traffic between the computer network and the internet. It protects the resources of the private network from the internal and external threats.

Windows XP Professional has built-in firewall software that allows the users to filter the incoming and outgoing traffic by applying different rules. The rules can be based on the IP addresses of the source and destination, port number, domain names and specific applications and protocols such as FTP, HTTP, Remote desktop, Telnet, SMTP, POP3 and Https etc. A firewall works closely with the router and many routers has the built-in firewall. The common functionalities include packet filtering, application gateway, proxy server and circuit relay.

Firewall Features:

The common features of a firewall program include the following.

Packet filtering

Ports blocking and scanning

Web filtering

URL Screening

Web caching

User blocking

Domain blocking

Antivirus

Spam Filtering

Email Scanning

Network Access Rules

Network Address Translation (NAT)

User Authentication

Intrusion Protection

Network Activity Monitoring

Types of Firewall:

Firewall can be categorized into the following two major categories.

Software Firewall

There are many software firewall products that are usually installed and configured on the Server computer. The most common software firewall includes Zone Alarm, Wingate, Barracuda spam firewall, Symantec Norton Personal Firewall, McAfee Personal Firewall Plus and Sygate® Personal Firewall PRO.

Hardware Firewall

A hardware firewall is a dedicated device that is usually attached with the gateway computer. Many routers provide have built-in firewall features. It filters the network traffic and blocks the unwanted traffic.

What is Firewall

A firewall is a software or hardware appliance that is used as a line of defense between your computer and the external threats from the internet. Firewall technologies have evolved to meet the security requirements of the IT infrastructure. In a computer network, a firewall solution is usually implemented at the gateway computer to block the threats like intruders, hackers, viruses and unauthorized access. There are different types of the firewall techniques and the implementation methods and the most commonly used techniques are packet filtering, proxy server, application gateway and the circuit-level gateway.

There are many companies that produce the firewall products and the most commonly used firewall products are manufactured by Zone Alarm, Microsoft Windows Firewall, Comodo, F-Secure, Kaspersky, LavaSoft, McAfee, Symantec, R-Firewall, AShampoo and Trend Micro PC-cillin.

Firewall works very closely to a router program by examining each packet of the data. A properly configured firewall prevent your computer form the internal and external threats. Most business class firewall products offer application layer filtering. Application filtering is required to prevent the spam, viruses and the application layers threats. Performance is very important in the busy networks and the firewall throughput can range from 150 mpbs to 1 gbps. Configuring the firewall requires the detailed understating of the network applications and the overall IT infrastructure. To select the best firewall product, you need to know your IT infrastructure and the level of security you require. Most of the firewall products posses the following features.

Computer Networking :

Computer networking is a linking of the network devices and computers with each other to provide the data communications and sharing the network resources such as printer, scanner, modem, CD/DVD and internet access. A computer network can be interconnected with the UTP/STP cables, coaxial cables, fiber optics and wirelessly through the radio waves. Today, no business can work effectively without the data communications within the organization. A network can be designed by different layouts known as topologies.

The common topologies include star, hub, mesh, hybrid and ring. Star topology is the most common topology in Ethernet based local area network. There are specialized rules and standards and based on these standards, the devices communicate with each other.

One of these specialized standards and agree up ways is known as protocols. TCP/IP is the protocol suite that contains the multiple communication protocols such as TCP, IP, SMTP, FTP, DHCP, LDAP, PPP, Telnet and many others. TCP/IP works together and it is the most common communication protocol for the LAN, WAN and internet. The communications on the internet is based on the IP addresses, which is a part of the TCP/IP stack. No computer on the internet or in the LAN/MAN/WAN can communicate without a unique IP address.

Networking and data communications provides the flexibility, easy of work and communications with each other and today every kind of business in the world, which involves more than one computer, require a computer network. A network can be setup by using the following things

• Computer with Windows/Linux operating system installed.
• Every computer requires a unique LAN card, which should be properly installed and configured.
• Ethernet cable with the RJ-45 connectors at both ends.
• A Router/Switch or hub.

The other devices are bridges, transceivers, terminal servers and gateways and they can be setup according to your requirements.

There are three main types of the computer network i.e. LAN, MAN, WAN, CAN, GAN and PAN and each network either be a peer to peer or client server network. In a client/server network model, a centralized domain controller is used to control all the computer network. It provides the services to the clients like logon authentication, printer access, scanner access, centralized data storage, user management, resources management, DHCP, DNS, FTP and internet access.

To communicate with the other computer, each computer should support the same protocol and the TCP/IP is the most commonly used protocol in a computer network. Internetwork is a type of computer network that connects the two or more different networks. There are three main types of the internetwork i.e. intranet, extranet and internet.

Troubleshooting

In this troubleshooting article, you will learn that how to solve the common problems of a PC By using the right techniques and tools today PCs are much easier to troubleshoot than before There are many troubleshooting and diagnostic utilities in the Windows based operating systems that help to solve the common configurations, connectivity and other hardware and software related errors. The PC components that are involved with the display are motherboard, processor, RAM, video card and power supply. If your errors are related to the display then the problem will be mostly likely to these components. If you PC does not boot up, make sure everything is plugged correctly and also check the CMOS battery, memory stick, power supply, power button, video card and the processor. If your PC hangs up or freezes it may be due to the hardware/software conflicts, faulty processor fan, inadequate RAM and a virus/spyware attack. To deal with the security related threats such as viruses, hacking attacks, spyware, adware, Trojan horses, browser hijacks and other, you need to install up-to-dated antivirus, anti spyware software and properly configured firewall software or hardware. This article will provide you help in troubleshooting the most common problems with your PC.

• Hard Disk Problems:

If you hard disk does not spin up then you need to do the following.

• Check the power connectors are properly connected.
• Check if the IDE ribbon cable is properly connected with the motherboard and hard disk.

If the problem still not resolved then there may be bad sectors or other physical defects in your hard disk। Use a hard disk diagnostic utility, it will diagnose the health status of your hard disk and will help you to troubleshoot the common problems.

• Printer Problems:

If your printer does not print, then you need to do the following.

• Check the cables.
• Restart the printer.
• Update the driver.
• Check the alignment of the printer.

If the problem is still not resolved then you need to reinstall the printer.

• Motherboard Problems:

A PC motherboard consists of an I/O ports, expansion slots, input device ports, RAM memory and CPU socket. A misconfigured motherboard may results in the system errors or no display at all. To troubleshoot the errors with your system’s motherboard you need to do the following.

• Double check the motherboard’s jumper settings
• Upgrade the drivers of the newly installed motherboard and set the BIOS according to the
• manufacturer’s manual.
• Remove all the optional devices and see if the problem is solved or not.
• Double check all the connections to the motherboard.
• Check the system’s BIOS and see if it is properly configured or not.
• Make sure that the keyboard and mouse are properly inserted into the motherboard

• Network Troubleshooting:

To troubleshoot the connectivity related issues in your computer network, you need to do the following:

• Update the drive of the LAN card.
• Check the network cable at both ends। It should be properly inserted at both ends i।e. one end in the hub/switch and one end in the computer.
• Restart the hub/switch or router.
• Restart your computer.

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