A Study On Computer Network Education Essay

Published: Last Edited:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software.

Network Design

Computer networks also differ in their design. The two types of high-level network design are called client-server and peer-to-peer. Client-server networks feature centralized server computers that store email, Web pages, files and or applications. On a peer-to-peer network, conversely, all computers tend to support the same functions. Client-server networks are much more common in business and peer-to-peer networks much more common in homes.

A network topology represents its layout or structure from the point of view of data flow. In so-called bus networks, for example, all of the computers share and communicate across one common conduit, whereas in a star network, all data flows through one centralized device. Common types of network topologies include bus, star, ring and mesh.


Area Networks

Networks can be categorized in several different ways. One approach defines the type of network according to the geographic area it spans. Local area networks (LANs), for example, typically reach across a single home, whereas wide area networks (WANs), reach across cities, states, or even across the world. The Internet is the world's largest public WAN.

Client Server Networks

Client and Server Devices

Client/server networking grew in popularity many years ago as personal computers (PCs) became the common alternative to older mainframe computers. Client devices are typically PCs with network software applications installed that request and receive information over the network. Mobile devices as well as desktop computers can both function as clients.

A server device typically stores files and databases including more complex applications like Web sites. Server devices often feature higher-powered central processors, more memory, and larger disk drives than clients.

Client-Server Applications

The client-server model distinguishes between applications as well as devices. Network clients make requests to a server by sending messages, and servers respond to their clients by acting on each request and returning results. One server generally supports numerous clients, and multiple servers can be networked together in a pool to handle the increased processing load as the number of clients grows.

A client computer and a server computer are usually two separate devices, each customized for their designed purpose. For example, a Web client works best with a large screen display, while a Web server does not need any display at all and can be located anywhere in the world. However, in some cases a given device can function both as a client and a server for the same application. Likewise, a device that is a server for one application can simultaneously act as a client to other servers, for different applications.



A LAN (local area network) is a group of computers and network devices connected together, usually within the same building. By definition, the connections must be high speed and relatively inexpensive (e.g., token ring or Ethernet). Most Indiana University Bloomington departments are on LANs.

A MAN (metropolitan area network) is a larger network that usually spans several buildings in the same city or town. The IUB network is an example of a MAN.

A WAN (wide area network), in comparison to a MAN, is not restricted to a geographical location, although it might be confined within the bounds of a state or country. A WAN connects several LANs, and may be limited to an enterprise (a corporation or an organization) or accessible to the public. The technology is high speed and relatively expensive. The Internet is an example of a worldwide public WAN.

A LAN connection is a high-speed connection to a LAN. On the IUB campus, most connections are either Ethernet (10Mbps) or Fast Ethernet (100Mbps), and a few locations have Gigabit Ethernet (1000Mbps) connections.


Some benefits of computer networks are given below.

  1. Computers which are connected through a network can share resources as hard drives, printers, scanners etc with each other.
  2. They can send file from one computer to another quite easily.
  3. You can connect all the computers which are connected through a network to the internetby using a single line. So it means that you can save the connection cost for each computer but you internet connection must be fast.
  4. IF you want to access data from the other computer which is the part of network then you can access data from that computer.
  5. can run those programs which are not installed on their computers but are installed on any other user's computer.



Network Operating Systems (NOS)

Network operating systems typically are used to run computers that act as servers. They provide the capabilities required for network operation. Network operating systems are also designed for client computers and provide functions so the distinction between network operating systems and stand alone operating systems is not always obvious. Network operating systems provide the following functions:

  • File and print sharing.
  • Account administration for users.
  • Security.

Installed Components

  • Client functionality
  • Server functionality

Functions provided:

  • Account Administration for users
  • Security
  • File and print sharing

Network services -

  • File Sharing
  • Print sharing
  • User administration
  • Backing up data

Network Operating System Examples

  • Windows NT server and workstation - Can use multiple processors and run on Intel or RISC computers. Performs preemptive multitasking.
  • Windows 95 - Cannot use multiple processors or run on RISC computers. It cannot use NT drivers, but it can use older drivers.
  • OS/2 - supports preemptive multitasking and multithreading and protects applications from each other. It runs on Intel or RISC computers. Supports 1 processor. Requires a minimum of a 386 and 8M of RAM. Some DOS drivers will work for OS/2. Won't run on DEC Alpha systems.
  • MacIntosh - supports cooperative and preemptive multitasking and uses a windows, icons, mouse environment for system control.




The Open Systems Interconnection (OSI) reference model has been an essential element of computer network design since its ratification in 1984. The OSI is an abstract model of how network protocols and equipment should communicate and work together (interoperate).

The OSI model is a technology standard maintained by the International Standards Organization (ISO). Although today's technologies do not fully conform to the standard, it remains a useful introduction to the study of network architecture.

The OSI Model Stack

The OSI model divides the complex task of computer-to-computer communications, traditionally called internetworking, into a series of stages known as layers. Layers in the OSI model are ordered from lowest level to highest. Together, these layers comprise the OSI stack. The stack contains seven layers in two groups:

Upper layers -

  1. application
  2. presentation
  3. session
  4. Lower layers -

  5. transport
  6. network
  7. data link
  8. physical

OSI Model Layers

The layers are arranged here from the lower levels starting with the physical (hardware) to the higher levels.

  1. Physical Layer - The actual hardware. Concerned with the connection between the computer and the network.
  2. Data Link Layer - Data transfer method (802x ethernet). Puts data in frames and ensures error free transmission. Also controls the timing of the network transmission. IEEE divided this layer into the two following sublayers.
    1. Media Access Control (MAC) - Used to coordinate the sending of data between computers. The 802.3, 4, 5, and 12 standards apply to this layer. If you hear someone talking about the MAC address of a network card, they are referring to the hardware address of the card.
    2. Logical Link control (LLC) - Maintains the Link between two computers by establishing Service Access Points (SAPs) which are a series of interface points. IEEE802.2.
  3. Network Layer - IP network protocol. Routes messages using the best path available. Concerned with message priority, status, and data congestion.
  4. Transport Layer - TCP, UDP. Provides properly sequenced and error free transmission. Recombines fragmented packets.
  5. Session Layer - Determines when the session is begun or opened, how long it is used, and when it is closed. concerned with security and name recognition.
  6. Presentation Layer - ASCII or EBCDEC data syntax. Makes the type of data transparent to the layers around it. Used to translate date to computer specific format such as byte ordering. It may include compression. It prepares the data, either for the network or the application depending on the direction it is going.
  7. Application Layer - Provides the ability for user applications to interact with the network.

Upper Layers of the OSI Model

OSI designates the application, presentation, and session stages of the stack as the upper layers. Generally speaking, software in these layers performs application-specific functions like data formatting, encryption, and connection management.

Examples of upper layer technologies in the OSI model are HTTP, SSL and NFS.

Lower Layers of the OSI Model

The remaining lower layers of the OSI model provide more primitive network-specific functions like routing, addressing, and flow control. Examples of lower layer technologies in the OSI model are TCP, IP, and Ethernet.

Benefits of the OSI Model

By separating the network communications into logical smaller pieces, the OSI model simplifies how network protocols are designed. The OSI model was designed to ensure different types of equipment (such as network adapters, hubs, and routers) would all be compatible even if built by different manufacturers. A product from one network equipment vendor that implements OSI Layer 2 functionality, for example, will be much more likely to interoperate with another vendor's OSI Layer 3 product because both vendors are following the same model.

The OSI model also makes network designs more extensible as new protocols and other network services are generally easier to add to a layered architecture than to a monolithic one.

Network Topology

Topology describes the method used to do the physical wiring of the network. The three topologies are:

  1. Bus - Both ends of the network must be terminated with a terminator. A barrel connector can be used to extend it. Computers are connected to the main cable in a line.
  2. Star - All devices revolve around a central hub, which is what controls the network communications, and can communicate with other hubs. Range limits are about 100 meters from the hub.
  3. Ring - Devices are connected from one to another, as in a ring. A data token is used to grant permission for each computer to communicate.

Many times these topologies are combined on a network to form a star-ring for token ring, or a star-bus.


A repeater connects two segments of your network cable. It re times and regenerates the signals to proper amplitudes and sends them to the other segments. When talking about, ethernet topology, you are probably talking about using a hub as a repeater. Repeaters require a small amount of time to regenerate the signal. This can cause a propagation delay which can affect network communication when there are several repeaters in a row. Many network architectures limit the number of repeaters that can be used in a row. Repeaters work only at the physical layer of the OSI network model.


A bridge reads the outermost section of data on the data packet, to tell where the message is going. It reduces the traffic on other network segments, since it does not send all packets. Bridges can be programmed to reject packets from particular networks. Bridging occurs at the data link layer of the OSI model, which means the bridge cannot read IP addresses, but only the outermost hardware address of the packet.


A token ring network uses a multistation access unit (MAU) as a hub. It may also be known as a Smart Multistation Access Unit (SMAU). A MAU normally has ten ports. Two ports are Ring In (RI) and Ring Out (RO) which allow multiple MAUs to be linked to each other. The other 8 ports are used to connect to computers.

Network Card Operations

Computer Bus and NIC Functionality

The NIC must have a transceiver of the correct type to transmit on its intended hardware media. Therefore when moving a NIC from one type network such as 10 Base2 and 10BaseT to the other, the adapter must be configured to use the correct transceiver (there are two connectors to support both types of network). The NIC has a permanent media access control (MAC) address which is used in order to tell what card data is for. The NIC converts between the parallel data format of the computer's internal data bus and the serial data stream on the network.

The card slots are used to put additional cards such as video cards, sound cards, internal modems, or network cards into. Some motherboards today include video and sound without the addition of a extra card. These cards slots today are mostly PCI type card slots. When talking about cards that are plugged into a PC you are talking about the expansion bus. The expansion bus is a means of a microprocessor extending its communication ability further into the outside world. It is a data exchange means between add on cards and the microprocessor and the motherboard. These busses commonly support 16 or 32 bit parallel communications as noted below. The larger the parallel bus, normally the faster the interface will be.

Peer to peer is an approach to computer networking where all computers share equivalent responsibility for processing data. Peer-to-peer networking (also known simply as peer networking) differs from client-server networking, where certain devices have responsibility for providing or "serving" data and other devices consume or otherwise act as "clients" of those servers.

Characteristics of a Peer Network

Peer to peer networking is common on small local area networks (LANs), particularly home networks. Both wired and wireless home networks can be configured as peer to peer environments.

Computers in a peer to peer network run the same networking protocols and software. Peer networks are also often situated physically near to each other, typically in homes, small businesses or schools. Some peer networks, however, utilize the Internet and are geographically dispersed worldwide.

Home networks that utilize broadband routers are hybrid peer to peer and client-server environments. The router provides centralized Internet connection sharing, but file, printer and other resource sharing is managed directly between the local computers involved.



Ethernet is a physical and data link layer technology for local area networks (LANs). Ethernet was invented by engineer Robert Metcalfe. When first widely deployed in the 1980s, Ethernet supported a maximum theoretical data rate of 10 megabits per second (Mbps). Later, Fast Ethernet standards increased this maximum data rate to 100 Mbps. Today, Gigabit Ethernet technology further extends peak performance up to 1000 Mbps.

Higher level network protocols like Internet Protocol (IP) use Ethernet as their transmission medium. Data travels over Ethernet inside protocol units called frames.

The run length of individual Ethernet cables is limited to roughly 100 meters, but Ethernet can be easily extended to link entire schools or office buildings using network bridge devices.

Token Ring

Developed by IBM, Token Ring, is standardized to IEEE 802.5. Token Ring uses a star topology, but it is wired so the signal will travel from hub to hub in a logical ring. These networks use a data token passed from computer to computer around the ring to allow each computer to have network access. The token comes from the nearest active upstream neighbor (NAUN). When a computer receives a token, if it has no attached data and the computer has data for transmission, it attaches its data to the token then sends it to its nearest active downstream neighbor (NADN). Each computer downstream will pass the data on since the token is being used until the data reaches its recipient. The recipient will set two bits to indicate it received the data and transmit the token and data. When the computer that sent the data receives the package, it can verify that the data was received correctly. It will remove the data from the token and pass the token to its NADN.

It can use UTP, STP, or fiber optic cable. Maximum cable length is 45 meters with UTP and 101 meters with STP. Topology is star-wired ring. Uses type 1 STP and type 3 UTP. Connectors are RJ-45 or IBM type A. Minimum length between nodes is 2.5 meters. Maximum number of hubs or segments is 33. Maximum nodes per network is 72 nodes with UTP and 260 nodes with STP. Speed is 4 or 16 Mps. IEEE 802.5 defines token ring. Data frames may be 4,000 to 17,800 bytes long.


IPX/SPX is a routable protocol and can be used for small and large networks. The following protocols are part of the IPX/SPX suite:

  • SAP - Service Advertising Protocol packets are used by file and print servers to periodically advertise the address of the server and the services available. It works at the application, presentation, and session levels.
  • NCP - NetWare Core Protocol provides for client/server interactions such as file and print sharing. It works at the application, presentation, and session levels.
  • SPX - Sequenced Packet Exchange operates at the transport layer providing connection oriented communication on top of IPX.
  • IPX - Internetwork Packet Exchange supports the transport and network layers of the OSI network model. Provides for network addressing and routing. It provides fast, unreliable, communication with network nodes using a connection less datagram service.
  • RIP - Routing Information Protocol is the default routing protocol for IPX/SPX networks which operates at the network layer. A distance-vector algorithm is used to calculate the best route for a packet.
  • ODI - Open Data-link Interface operates at the data link layer allowing IPX to work with any network interface card.

NetWare frame types

The following frame types may be used:

  • Ethernet 802.2
  • Ethernet 802.3
  • Ethernet SNAP
  • Ethernet II

Novell NetWare 2.x and 3.x use Ethernet 802.3 as their default frame type. Novell NetWare 4.x networks use Ethernet 802.2 as their default frame type. If communication does not occur between two NetWare computers it is a good idea to check the netware versions of the two computers to be sure their frame types match. If the frame types do not match on an ethernet network, the computers cannot communicate.

In Novell systems, the client software is referred to as a requestor.


LAN - Local Area Network

A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In TCP/IP networking, a LAN is often but not always implemented as a single IP subnet.

In addition to operating in a limited space, LANs are also typically owned, controlled, and managed by a single person or organization. They also tend to use certain connectivity technologies, primarily Ethernet and Token Ring.

WAN - Wide Area Network

As the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning the Earth.

A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.

A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by any one organization but rather exist under collective or distributed ownership and management. WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity over the longer distances.

LAN, WAN and Home Networking

Residences typically employ one LAN and connect to the Internet WAN via an Internet Service Provider (ISP) using a broadband modem. The ISP provides a WAN IP address to the modem, and all of the computers on the home network use LAN (so-called private) IP addresses. All computers on the home LAN can communicate directly with each other but must go through a central gateway, typically a broadband router, to reach the ISP.

TCP/IP protocols include:

  • FTP - File Transport Protocol at the application layer.
  • Telnet - Remote session at the application layer.
  • SMTP - Simple Mail Transport Protocol at the application layer.
  • DHCP - Dynamic host configuration protocol is used to assign IP addresses dynamically to network cards. It works at the application layer.
  • TCP - Transport Control protocol is a connection oriented reliable protocol working at the transport layer.
  • UDP - User Datagram Protocol is a connection less unreliable protocol working at the transport layer.
  • ICMP - Internet Control Message Protocol is used to perform network error reporting and status. It works at the transport layer.
  • IGMP - Internet Group Management Protocol is used to manage multicast groups and it works at the transport layer.
  • IP - Internet Protocol is used for software addressing of computers and works at the data link layer.
  • ARP - Address Resolution Protocol is used to resolve the hardware address of a card to package the ethernet data. It works at the data link layer.
  • RARP - Reverse Address Resolution Protocol used for disk less computers to determine their IP address using the network. It works at the data link layer.



To design any network layout, it is important to know the basic LAN topologies and to consider their advantages and disadvantages. There are basically three topologies, and we can choose according to our need.

  1. Bus topology
  2. Star topology
  3. Ring topology

These were the basic topologies for designing any local area network. We can choose any according to the size and the need of our network.

The basic steps are:

  • Draw a rough sketch of your network (where the computer will be, main switch, etc.)
  • Consider all the topologies carefully.
  • Choose the one that suits most of your requirements.

For wires, the most suitable are:

  • Coaxial for bus topology.
  • UTP for star topology.
  • STP for ring topology.
  • Install. However, it would be safer that you employ technicians for the job.
  • Check the network.


Geographical considerations: Consider the LAN and WAN links that may be required. Offices that are separated by large distance (for example one in Delhi and another in New York) can be linked together by a WAN (Wide Area Network) link. Similarly, building complexes within a compound can be linked by a LAN (Local Area Network) link. Typically, the LAN links are high bandwidth (10Mbps and above) and WAN links are of lower bandwidth (64 Kbps - 2Mbps). Further, the LANs fall within the premises of a Company whereas WANs are typically leased and maintained by the Telecom. Hence, WANs are costly in bandwidth terms and need to be planned and designed with utmost care to minimize resource consumption.

Cost considerations: For LANs, the tendency is to minimize the equipment cost. That is minimizing the cable cost, minimizing the per port cost, and the labour cost. For WANs the primary goal is to minimize the usage of the bandwidth. This is because, the recurring costs for bandwidth are normally much higher than the equipment or labour cost. Therefore more weightage is given to reliable equipment, and efficient utilization of bandwidth. Some factors that optimize cost are:

  • Improve efficiency on WAN circuits by using features such as compression, Voice Activity Detection etc.
  • Use technologies such as ATM that dynamically allocate WAN bandwidth.
  • Integrate both voice and data circuits
  • Optimize or eliminate under utilized circuits.



In below I have shown how to set up a network for Salon Iris Co. They need to follow the following steps-

Network Setup

Setup Server Computer

The server is the computer that contains the Salon Iris database. The other computers are called clients. The client computers get information from the server computer. Any changes you make on the client computers will be saved on the server computer's database. Generally, the faster or most heavily used computer should be the server. The server computer must be on for the client computers to run the software. The server is also the only computer that will be able to backup the database, so it is recommended that this computer contain a Zip drive, CD writer, or be able to utilize a USB memory stick (thumb drive).

On the server, we need to perform the following steps:

  1. While in Windows, insert the Salon Iris CD in the CD ROM drive. Or, download the software by clicking the Download Now button below. The installation process should begin.
  2. If you use Windows XP (Service Pack 2), if the installation process does not begin, click the Start button on the Windows desktop. Select Run. At the prompt, type d:\launch (where d: is the letter of your CD ROM drive). If you use Windows Vista, hold down the Windows key, which is located next to the Alt key, and press the R key. At the prompt, type d:\launch (where d: is the letter of your CD ROM drive). Your CD ROM drive could also be the e: drive, depending on your computer's configuration.
  3. If you are downloading this file from the Internet, the Open File - Security Warning screen will appear. Click the Run button. Salon Iris is free of viruses and is perfectly safe to run on your computer.
  4. The InstallShield Wizard screen will appear. Click Next.
  5. The License Agreement screen will appear. Carefully and slowly read over the license agreement. If you wish to accept the terms in the license agreement, select I accept the terms in the license agreement and click the Next button. If you do not accept the terms, Salon Iris will not install and you can stop using Salon Iris.
  6. Leave the default destination folder as C:\Program Files\ Salon Iris\ and click Next.
  7. Click the Install button. Salon Iris will automatically install SQL Server. This process will take a few minutes.
  8. Click the Finish button.
  9. The Salon Iris icon will now appear on your computer's desktop. Double click on the Salon Iris icon.
  10. The First Time Setup screen will appear. Select Register and click OK.
  11. Enter your business's name and serial number. Your serial number was given to you at the time of purchase of Salon Iris and is also found on the sticker that comes with your Salon Iris CD. Keep the serial number in a safe place and do not lose it.
  12. Click the OK button.
  13. 7
  14. The Registration Successful screen will appear. Click OK.
  15. The Select Server screen will appear. Select This computer is the server.
  16. Click the Auto Setup button. In most cases, Salon Iris will automatically connect to the instance of SQL Server found. If more than one instance of SQL Server is found on your computer, you will be prompted to select which instance to use. From the list of available instances of SQL Server, select which instance you would like to connect to and click OK.
  17. If Salon Iris does not connect to an instance of SQL Server, click the Auto Setup button again. If you still have an issue, restart your computer and when you open Salon Iris, you may be prompted with the No Database Open screen. Click the Select Server button and repeat step 15.
  18. Select which type of database that you would like to start with. You can select either of the following choices:
    1. Sample Database, select this choice if you would like to start using Salon Iris with some sample clients, products, and appointments. We recommend using the sample database with the trial version of Salon Iris.
    2. Blank Database, select this choice if you would like to start using Salon Iris with a totally blank database
  19. 18. Click OK. Click OK again.
  20. 19. After the database has been created, the Set Database Password screen will appear. Salon Iris will ask for a database password every time it is opened or when you restore a database from a backup. Enter your database password and then retype it. Be sure to take careful note of your database password spelling in UPPER and lower case. Passwords are CaSe sensitive. Keep the password in a safe place as CMJ Designs Inc. does not replace database passwords. Click the OK button.
  21. 20. Salon Iris will let you know that your database password was successfully set. Click OK.
  22. 21. You are now ready to setup your client computers.
  23. 22. After you register Salon Iris, Salon Iris (on each computer on the network) will need to be activated. Next time you close and re-open Salon Iris, Salon Iris will walk you through how to activate it. You can activate it over the Internet or via phone. Complete step-by-step instructions that are very easy to follow, will be shown on the Salon Iris screen. Follow the instructions for activation. If you are on a payment plan, you are not required to activate until you complete the payment plan. If you are leasing the software, you are not required to activate the software.



Virus Protection & Network Security

Anti-Virus Requirement

Over 10,000 computers are now connected to the campus network through the residential computer network. Unprotected computers contribute to the impact of attacks by computer viruses, worms and other malicious programs. On-Campus Housing (OCH) requires all residents with Windows, Macintosh and Linux operating systems to use and regularly update anti-virus software on their computer(s). OCH is providing Sophos anti-virus software as part of your housing contract. OCH took this measure to reduce risks to the UCLA data network and its users.

Please be aware that even with the best protection, it is possible for your computer to get infected with a virus. Should this occur, you will find your internet access severely limited until the Student Technology Center (STC) can verify that the computer system is clean of all viruses. If you have any further questions, please feel free to contact the STC.

Note: The STC will have a proactive role in virus prevention by providing you with anti-virus software, but due to the nature of viruses, you may still get infected. In such a case, the STC cannot be held responsible for damage, loss of data or repair fees.

Additional Responsibilities

  • Install any recommended security patches for the operating system and applications.
  • Use a firewall. For Windows XP and Vista, use the one provided with the operating system.
  • Exercise caution when opening attachments. Never open an attachment unless it is expected.
  • Exercise caution when downloading files from the Internet. Only download from reputable sites.
  • Exercise caution when installing files from removable media such as CDs. Even "shrink-wrapped" software has been known to contain viruses.
  • If your computer is known to be infected, remove it from the network until it can be disinfected. (Contact the STC if you need assistance).
  • If the STC responds to a virus incident and finds that the infected desktop system is not running virus protection software, then the individual will be required to install OCH provided Sophos Anti-virus software to prevent future incidents.
  • Read the AUP (Appropriate Use Policy). Allowing a computer system to become infected puts other UCLA systems at risk.
  • If your computer is reported or found to have been infected, your network connection will be quarantined and you will need to either remove the infection or bring your computer to the STC for disinfection.

Security Terminology

Trojan Horse: A malicious, security-breaking program that is disguised as something benign, such as a directory lister, archiver, game or other software.

Virus: A cracker program that searches out other programs and "infects" them by embedding a copy of itself in them, so that they become Trojan horses.

Worm: A program that propagates itself over a network, reproducing itself as it goes.


The firewall protects a network from malware or hackers to an external network. The firewall filters potentially harmful traffic entering or leaving. Firewalls are the Member States within the networks on the Internet. It also protects computers. The five, the deployment of firewall packet filter, application filters, proxy servers, circuits and Stateful Inspection.

  • • Packet Filtering: A firewall packet filtering, each packet of the conversion of the unit. It also controls the packet headers of all packets on the network firewall.
  • Source IP Address: It is the host of the suite. Striker of this area can be in an attempt to IP spoofing of conduct. Firewall is configured so that packets that arrive at the external interface or an error in the host or the attempt to IP spoofing. Objective of the IP address: This is the IP address that tries to achieve.

    IP-ID: Each IP is a protocol that follows. For example, TCP (Transmission Control Protocol), Article 6, UDP User Datagram Protocol) Article 17, and Internet Control Message Protocol (ICMP) is ID-1.

    Fragmentation Flags: firewall, review and transfer or deny packets fragmented. The success of a fragmentation attack can allow an attacker to packets which could be an internal host.

    IP Configuration Options: This field is used for diagnosis. The firewall is for submission of packets on the network, in relation to this area. Hackers can in this area, in conjunction with IP spoofing to redirect the network packets to select.

  • • Apply filters: This property allows listening connections and conducts safety inspections. The firewall acts as a proxy for connections between the internal and external network. The firewall rules on monitoring access to certain applications. It is also for e-mail virus installations. These firewalls are often considered as E-mail gateway.
  • • Proxy Server: A proxy server takes the responsibility for the provision of services between the internal and external network. Proxy server can be used for the diagram of the address space of the internal network. It can also be used for applications based on the protocol and address.
  • • Circuit level: a control circuit on the firewall ports TCP and UDP, but do not watch the data on them. If a connection is established, the traffic is, without further consideration.
  • • Stateful Inspection: A firewall, control of the network layer. It evaluates the information in IP header. It also monitors the status of each connection. The links are rejected when they try to take measures which are not standard protocol. The firewall features can be referred, together with an application firewall. A lot of series firewall is a common practice to improve security in the perimeter network.


After analysing everything I would like to say that our network system will be vulnerable if our security system becomes weak. So we have to be very careful that no unauthorised person can access our system without our permission.Thats all.


    Computer networking : a top-down approach / James F. Kurose, Keith W. Ross ; international edition a Kurose, James F. Boston, MA : Pearson/Addison Wesley, 2008

    Computer networking and the Internet / Fred Halsall. Halsall, Fred. Harlow : Addison-Wesley, 2005.

    Computer networking with Internet protocols and technology / William Stallings. Stallings, William. Upper Saddle River, N.J. : Pearson/Prentice Hall, 2004.

    An engineering approach to computer networking : ATM networks, the internet, and the telephone netwo Keshav, Srinivasan. Reading, Mass. ; Harlow : Addison-Wesley, c1997.

    Online available at-