Evaluate the benefit of Linux operating system as interoperable and alternative NOS for the company in the form of a feasibility report to include the following:
Microsoft Windows is a series of computer operating systems and GUIs (Graphical User Interfaces) produced by Microsoft Corporation. Windows was the first operating environment introduced by Microsoft in 1985 as an add-on to MS-DOS. Windows was introduced because of the growing interest in Graphical User Interfaces (GUIs). Then Windows dominated the world’s personal computer market, overtaking the Mac OS, which had been introduced previously. Microsoft has introduced two parallel routes in their operating systems. One route is for Home users and the other route is for Professional IT users. The home versions have greater multimedia support and less ability for network and security. But Professional versions have low multimedia capabilities and better networking and security. Windows operating systems are commercial products and we should purchase license in order to use the products. And also the source code of windows products are closed and owned by Microsoft. Linux is a free and open source Operating System referring to Unix-type operating systems originally created by Linus Torvalds with the support of developers all over the world. Linux source code is freely available to everyone and anyone can freely modify and redistribute both commercially and non-commercially. Linux kernel can be defined as one of the best kernels that uses today. And further, many organizations have begun to use Linux based operating systems because of its high security and low cost. Linux is well known for its use in servers. And also Linux can be installed on vast variety of hardware, such as mobile phones, watches, mainframes, supercomputers and etc. Fedora, Suse, Mandriva, Ubuntu, Kubuntu and Red Hat are some popular distributions of Linux.
Security is a vital feature that every Operating System (OS) should provide. Because operating system is a key requirement of every computer system. Therefore everything depends on it. Malware or Malicious Software is a computer program that is designed by computer criminals in order to damage the systems and theft important information from computer systems. Therefore a network OS should have a thorough security. Without security, the network is vulnerable to larger number of threats.
Microsoft Windows OS is the most popular operating system in the world. It runs nearly 90% of desktop computers in the consumer market, and is the main operating system of the vast majority of commercial and institutional users. Therefore this makes windows equipped machines larger target of malware (or malicious software) which is written by computer criminals who want to cause much damage to the system. According to the surveys that conducted by Kaspersky Lab have revealed that more than 11,000 malware programs for windows were discovered just in the second half of 2005. And also nearly one million Windows based computers have been infected with Botnets (Botnet is a small computer program used to control other computers remotely). In windows based computer systems some malware are very hard to remove without using an Anti-Malware program.
In year 2006 approximately 800 Linux malware were discovered. Most of the malware are propagated through the Internet. Usually Linux based malware are extremely rare. But there may have a possibility of spreading malware to the Linux based systems if they are connected with Windows based systems. Because of the rarity of malware threats, there is no initial requirement for Anti-Malware programs in Linux based systems. But anti-malware software such as ClamAV and Panda Security are rarely used for Linux servers for more security.
Computer Network is a set of interconnected computers that is used to share resources such as printers, scanners, information, storage and etc. Therefore operating systems should support for reliable resource sharing. Reliable resource sharing increases the network’s performance. Linux and Windows belong to two different platforms. Though they provide different facilities, they provide they initial requirements of a network. Usually Linux performs well for file sharing and Windows performs well for Printer, Scanner and other hardware resources sharing.
For desktop or home use, Linux is very cheap or free, and Windows is so expensive. For sever use, Linux is very cheap when comparing with Windows. Microsoft allows a single copy of Windows to be used on only one computer. In contrast, once we have purchased Linux, we can run it on any number of computers for no additional change. For instance in year 2005, Windows XP Professional Edition was sold for $200 and Windows Server 2003 Standard Edition with 10 Client licenses was sold for $1,100. But we can download Linux distributions freely from their web sites. Otherwise we can purchase a assorted distributions of Linux in a box with CD and manuals and technical support for around $40 to $80.
All software has and will have bugs (programming mistakes). Linux has a reputation for fewer bugs than Windows. Windows is developed by faceless programmers whose programming mistakes in Windows are hidden from the outside world because Microsoft does not publish the particular source code for Windows. Microsoft believe that their source code as a trade secret. In contrast, Linux is developed by hundreds of programmers all over the world. They publish the source code of the operating system to the world. Therefore it is stronger and less vulnerable for threats. That is why most of the organizations use Linux for their networks. Linux is getting update from many talented programmers all over the world.
When comparing with Linux network configuration, Windows configuration is easier. Because of generally Windows is based on GUI (Graphical User Interface). Therefore anyone can understand Windows based network configuration without having much knowledge. But Linux is generally based on Command Line or Terminal and there should have a good knowledge about Linux in order to implement a network by using Linux.
In Windows based systems the support NTFS, FAT, ISO 9660, UDF and others. But in Linux based systems they use ext2, ext3, ext4, ReiserFS, FAT, ISO 9660, UDF, NFS, JFS, XFS, and others. When comparing with Windows, Linux supports for many file systems. But now Windows has 3rd party drivers for ex2, ex3, ReiserFS, HFS and others.
Windows operating systems based on the NT kernel and it much more stable than the other older versions of Windows. But if we are using unsigned or beta drivers, it can lead to decreased system stability. Linux window manager is a key component of X-Windows based GUI system and can be highly stable. Mechanisms used to terminate badly behaving applications exist at multiple levels, such as Ksysguard and the kill command. If the GUI fails Linux can use a text based system. This feature is a powerful feature in Linux for network stability.
Within this task I used Fedora 12 instead of Ubuntu. Windows and Fedora belong to two different platforms. Therefore their mechanisms are different. That is why the feature interoperability is needed. Interoperability can be defined as the ability to work with each other. In order to exchange messages between each different platform reliably without any errors or misunderstandings, there should have a common background between each platform. Likewise Windows and Linux (or Fedora 12) also has that kind of common grounds that support for exchange messages between each platform.
Samba can be defined as a re-implementation of SMB/CIFS networking protocols. It was developed by Australian Andrew Tridgell. It provides various facilities for file and printer sharing between Windows, UNIX and UNIX like systems such as Linux, Solaris, AIX, and Apple’s Mac OS X server systems. Samba runs on most systems and now it has become a standard of most of the distributions of Linux (such as Fedora, Redhat, Mandriva, Suse and etc). When we need to share files and printers between different platforms such as Windows and Fedora, we should have to configure Samba. That is how we make interoperability between each platform.
DHCP is short for Dynamic Host Configuration Protocol, a protocol used for assigning dynamic IP addresses to devices on a network. With a dynamic addressing, a device can have a different IP addresses every time it connects to the network. Though some systems and devices are allow to change the IP addresses while it is still connected, DHCP also supports a mix of static and dynamic IP addresses. DHCP simplifies the network administration because the DHCP server keeps the track of IP addresses rather than requiring an administrator to manage the task. I consider that the DHCP is also an interoperability feature because it can assign IP addresses to any platform such as Windows and Fedora. When a LAN network has a mixture of a Windows and Linux based computers, DHCP can assign IP addresses to all computers without a barrier of the platform.
The X Windows system is a windowing graphical user interface that almost, but completely, entirely unlike Microsoft Windows and the Macintosh. This X Windows System is an open, client/server system that for managing a windowed graphical user interfaces in distributed network. Earlier UNIX based systems used Shell as an interface. Shell is an inbuilt special program that allows users to enter commands in a CLI or Command Line Interface. But the new versions of UNIX-like systems heavily use X Windows as a Windows like graphical user interface. Earlier it was very difficult to work with Windows and Linux through CLIs. Because of Window was completely GUI (Graphical User Interface) and Linux was completely CLI. But now the new distributions of Linux come with the X-Windows capability. Therefore now the both systems can work more reliably and easily as a whole. X Windows is also an interoperability feature that is provided by Fedora 12 in order to work with windows systems much easily.
TCP/IP shorts for Transmission Control Protocol and Internet Protocol. Generally it is a protocol suit that is used for the internet. It provides easy communication across different platforms and provide basis for the global internet. And also it can be defined as a basic communication language or protocol of the Internet. It can also be used as a communications protocol in a private network (either an intranet or extranet). When we set up with direct access to internet, our computer is provided with a copy of the TCP/IP program just as every other computer that we may send messages to or get information from also has a copy of TCP/IP. In an intranet there may have computers with different platforms such as Windows and Linux. But using TCP/IP protocol we can connect these computers. Both Windows and Linux distributions support for TCP/IP. Therefore it can also be considered as an interoperability feature of Windows and Linux.
DNS is Short for Domain Name System. DNS is an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they’re easier to remember. The internet is based on IP addresses. Every time when we use a domain name, DNS server must translate the name into the particular IP address. In intranets also some organizations use DNS servers to name their network computers. Though it is a Windows based computer or a Linux system, it carries out its task perfectly. Because DNS also has a interoperability feature to work with different platforms.
For this Task I used Fedora 12 instead of using Ubuntu. Because Ubuntu do not have an inbuilt a Samba server facilities and it should be downloaded as a third party tool. But Fedora 12 has those facilities for printer and file sharing.
Performance is a vital part of a network. The efficiency of a network depends on the hardware and software performance. To the bank’s network I used one of the distributions of Linux called Fedora 12 as the NOS (Network Operating System). Generally Linux based operating systems are lightweight and need low performances. As the other distributions of Linux, Fedora 12 is also a lightweight operating system that requires low performance hardware. Bank is a place where many transactions are taken place every second across their branches and other networks. Therefore the bank’s network should be stable and reliable. Due to these reasons a bank should use trusted and reliable hardware and software in order to increase their network performances. Usually the costs of network devices are relatively high in the modern market. And also the network operating systems like Windows are extremely expensive. Therefore by using a free and open source OS like Fedora 12 we can reduce the money wastage. Further it does not need high performance computers for installation and does not consume lots of hard disk space like Windows does. Fedora 12 provides online updations and does not have a limit on installation. One copy of Windows can be installed to a one computer only. Otherwise we have to buy license. But Fedora 12 can be installed to any number of computers without any limitations. According to those above reasons I think that Fedora 12 provides good performances and also it is more cost effective when comparing with Windows.
Security is a key requirement of a network. Otherwise anyone and any malware can attack and theft the important information from the network. Therefore OS (Network Operating System) developers try to increase OS’s security features. If there’s no security within an OS, then it is totally fails. Fedora 12 is a distribution of Linux and it is categorized as Free and Open Source Software. Linux based systems and their source codes are freely available to anyone and can be modified as required. Fedora 12 has also been developed by many programmers all over the world and it is a strong operating system. But windows based systems are commercial OSs and they do not publish their source code to the public. Therefore it is developed by limited programmers and there security is also limited. That is why we need third party security tools to protect windows based systems. The third party trusted and reliable Anti-Virus guards or third party security systems are more expensive and it is an additional cost to the windows based systems. But Fedora 12 has a strong in-built security mechanism (but Windows don’t have) such as DPI (Data Packet Inspection) and ISD (Intrusion Detection System). Because it is developed by many programmers all over the world. Therefore it doesn’t need any third party virus guards. The cost for additional security efforts has reduced in Fedora 12. Therefore Fedora 12 is a cost effective operating system when comparing with Windows. And also it is the best choice for a cost effective bank’s network system.
Computer operating systems and other software are not 100% perfect. That is why the manufactures provide support for their products. When a problem is taken place in a system, we can get the manufacturers’ support to solve the problem. And also manufactures provide patches and other updations to reduce the vulnerabilities of their products. Microsoft Windows also provide free updations and online support for their products after they are purchased. Though Windows provides free online support services for their products without any payments, Fedora and other Linux based operating systems do not provide free support services. If we need to get a support from Linux based system, we should pay some amount of money for their service. But they provide 24 hours update service for their products. In Fedora should have to pay for their services. Though the support service is not cost effective for the bank, the OS is totally free for download.
After installation and Configuration every computer system need to be well maintained. Windows systems are much easy to maintain because it doesn’t need well trained persons (compared with Linux). But Linux systems are more complex and cannot install, configure and maintain if there’s no knowledge of it. In order to maintain the Fedora system in the bank, the bank needs a well trained personnel or network administrator. Anyone cannot maintain a Linux system; therefore the cost of a Linux based network system administrator is higher when comparing with a Windows Network System Administrator. Manufactures support is always need for system maintenance. But we need to buy the service advices in Fedora form its manufacture.
Research and produce a comprehensive project plan for the implementation of a VPN within the company. This should include the following:
Although the topic VPN or a Virtual Private Network is a much complex subject in networking field, the basic idea of a VPN is quite simple. A corporation may have a number of officers (or group of officers) in different locations, and each of these locations can have its own local network. In many corporations there are many employees working remotely by connecting to the corporation’s local network at home or on the road. And also business partners can join together in extranets to share business information. Interconnecting these separate networks and locations over a public network is called a VPN or a Virtual Private Network. The apparent simplicity of VPN makes us think that it is a simple concept. But there is an ever-increasing number of VPN types, and a huge range of technologies for implementing VPNs are available today. This makes us easy to decide the most appropriate VPN solution for our need. The most common way to interconnect sites has been to use ATM or Frame Relay (FR) leased lines supplied by a service provider. The following parts of this task describe the VPN technologies, cost effective hardware and software solutions and responsibilities and level of services required from the ISP (Internet Service Provider).
As I mentioned above, VPN is a complex subject in networking. Therefore different sort of VPN technologies are introduced for different purposes. These technologies provide secure and cost effective solutions for telecommuters, home based workers, road warriors, remote sales people, mobile executives and also for global business. Within this task I expect to provide a short description about the current VPN technologies that are widely used today. I divide these technologies into two major parts such as Hardware Technologies and Software Technologies. According to my perception, I believe that the VPN protocols that are used to establish a VPN connection should also be a part of the software technologies. Because these protocols are created by using specialized algorithms and programming languages. Therefore I consider those protocols as Software Technologies within this task.
PPTP (Point-to-Point Tunneling Protocol) and L2TP (Layer 2 Tunneling Protocol) protocol technologies are heavily based on this PPP (Point-to-Point protocol) technology. PPP was designed to send data across dial-up or dedicated connections. PPP technology is used to encapsulate IP packets within PPP frames and then transmits the encapsulated packets across a point-to-point link. PPP was specially designed to use between dial-up clients and NASs (Network Attached Storage).
PPTP is one of VPN’s first protocols built on PPP (Point-to-Point Protocol) to provide remote access for VPN solutions. PPTP technology encapsulates PPP frames in IP datagrams using GRE or Generic Routing Protocol. PPTP uses authentication techniques within PPP. PPTP can be used for remote access and router-to-router VPN connections. The Point-to-Point Tunneling Protocol (PPTP) uses TCP (Transmission Control Protocol) connection for tunnel management and GRE for encapsulation.
L2F was designed to transmit data from corporate sites to their users by using tunnels. This protocol or VPN technology was first implemented in CISCO products. L2F doesn’t depend on IP and it’s the only way that it differs from PPTP. This protocol accepts other authentication mechanisms and allows tunnels to support more than one connection. L2F uses PPP for authenticate the remote user and it’s done twice at the ISP and then the second at the gateway to the connecting LAN. This is a Layer-2 protocol and handles IPX and NetBEUI as well.
L2TP is a combination of L2F and PPTP and it exists in the second layer of the OSI reference model. That is why it named as Layer 2 Tunneling Protocol. L2TP is defied for packet media, Frame relay, ATM and X.25. It has its own tunneling protocol and uses PPP’s PAP and other advanced mechanisms for authentication. Its encryption method is based on IPSec (Internet Protocol Security).
IPSec is a solution for VPN security and it exists in the third layer of the OSI reference model. IPSec uses number of encryption technologies to provide confidentiality and integrity of data. IPSec allows senders to authenticate and encrypt each packet. There are two modes of IPSec such as Transport mode and Tunnel mode. These two modes depend on the situation of security and traffic. Transport mode authenticates and encrypts the transport segment of an IP packet, and tunnel mode authenticates and encrypts the whole IP packet.
VPN Client software provides protected access to corporate resources via wireless, broadband, and dial-up connections with robust encryption and broad support across multiple connection types. Most of the modern VPN software simplifies the configurations of security policies and management of certificates through its graphical user interface. Microsoft, Netgear, Stone Gate and CISCO are some popular manufactures for VPN client software (But each of these manufactures use different sort of technologies to implement these VPN client software).
In network communication, data are transferred in the form of packets. Usually a router is a hardware device or a computer that looks at the IP packets and decides how to forward it. Routers operate at the network layer of the OSI reference model and that is used to connect networks or connect the networks to the internet. When a packet is received from the NIC (Network Interface Card) card, the router reads the IP address on the packet and forwards it to the appropriate network interface. The packet forwarding depends on the IP address and routing information that contains in the packet header. Even if the network architecture differs, the router has the capability to connect them. Though it can connect different network architectures, I cannot transform data from one data format to another (TCP/IP to IPX/SPX). Software for VPN router functions or normal router functions can be added to a server or a specialized computer that is optimized for communication.
VPN Concentrator is a device that is used to combine several communications channels into one. And also it is further used to tie multiple terminals together into one line. Although a device called Multiplexor carries out the same function as VPN concentrator, the total bandwidth of the concentrator’s inputs is not equals to its outputs. The concentrator has the ability to store data temporary but the multiplexor does not have this ability. An Ethernet hub, which is a multiport repeater, is sometimes called as a “concentrator”.
Although a VPN Gateway can be implemented as both Hardware and Software, I consider this as a hardware technology because for the ease of categorization. VPN Gateway is a device (can be a Hardware/Software) that is used to convert packets from one network protocol to another. Gateway acts as an entry and exit point of data where some kind of processing is done on the information that passes through it. Sometimes the VPN Gateway also called as a router or Layer 3 Switch. Gateway is a device that is used to join two networks together. It can be implemented completely in hardware, completely in software or as a combination of both.
Firewall can be implemented as both hardware and software or as a combination of both. But I included VPN Firewalls in the VPN Hardware category because for the ease of categorization. Network security is a major need of an organization. Firewall is one such solution that allows the computer to prevent unauthorized access of any application on the computer. Firewalls monitor traffic in the computer or the network. This monitoring can be done by the software in the computer or router. When using a VPN in an organization, the organization has a great requirement of using a firewall solution. Because of there may have a possibility of unauthorized access to the organization’s confidential information. By using VPN firewall technology we can reduce the outside threats. Even though the above technologies directly look like just software and hardware, they all have a complex technology encapsulated within them. The above VPN technologies are widely used within the modern VPNs.
Due to the requirements of the bank I designed a VPN that provides cost effective networking solutions. The bank needs their agents and branches to connect to the bank’s network secure through VPN. Therefore I designed a network that provides the above facilities. When designing the bank’s network I assumed that the particular bank is the head office and the agent is another organization. Although the bank may have many agents and branches, I’ve mentioned only one agent and a one branch within this network overview. Banks’ head office is the place where many of the confidential information about the transactions are stored. Therefore its network should be more secure than any other else. According to my VPN design I connected the bank’s network to the internet through an ISP (Internet Service Provider) in order to get the VPN access. The bank connects with the ISP directly using a VPN Router (this router is highly configured and cannot be accessed by the unauthorized VPN clients). Then I added a DMZ (Demilitarized Zone) in order to secure the LAN network from the unauthorized access. If the File server was implemented within the DMZ, it may vulnerable to the threats and there may have a possibility of information thefts. Therefore I implemented the File Server far away from the DMZ and it’s secured with two highly configured firewalls. Though someone can get into the DMZ in order to access the Web Server, he/she cannot penetrate the other firewall without proper authenticate information. All the computers within the Bank’s network can access the WEB server and File server according to their assigned privileges. Other agents and branches have rights to access the bank’s network (using Router to Router connection). Even though the VPN Routers and Firewalls (Hardware) are much expensive, they provide a great security to the Bank network. In order to reduce the software cost I recommend free and open source software for both servers and clients such as Linux, Open Office and etc.
According to my VPN design I need several kinds of software and hardware to implement the network. Therefore I’ve chosen some products to which supports for VPN. Some products are little bit expensive but provide high security and reliable service to the banks network. When choosing the software to the network implementation, I’ve chosen some widely needed software.
The Barricade router which has built-in VPN support is an ideal networking solution for VPN. This router consists of load balancing WAN ports, DMZ (Demilitarized Zone) port and a 10/100 LAN port. It has a built in firewall to protect the network from the edge. This router supports protocols such as TCP/IP, VPN connections with PPTP and IPSec. The in-built firewall provides a great protection against DOS attacks (Denial of Service attacks) and also it provides flexible Access Control. This router has the ability to access remote corporate network securely through an authenticated and encrypted tunnel over the internet.
NetGear Pro-Safe switch is suitable for high-speed network on a small scale. This switch consists of five auto-speed-sensing 10/100/1000 Mbps UTP ports. And also this it has the capability to handle huge workloads (this feature is more useful because of the Web Server is connected to this switch within my VPN design). This switch can move large files across the network instantly and let devices to connect to the network painlessly. The metal chassis protects the interior working parts from physical damages.
The CISCO FastHub 424 10/100 of high-performance Fast Ethernet repeaters deliver unmatched flexibility and low-cost managed connectivity to the desktop. The FastHub 424 10/100 provides ultra low-cost 10/100 autosensing desktop connectivity where dedicated bandwidth is not required. The FastHub 424 will be deployed as a high-performance solution for providing 10/100 Fast Ethernet connectivity to the desktop. This hub provides dedicated connections over extended distance (up to 2Kms) to upstream switches or routers.
NetGear ProSafe FVS338 Firewall supports for 50 VPN Tunnels for Encrypted Remote Access. This VPN firewall with 8 Port 10/100 switch and Dial Back-up is an SNMP-Manageable, High Performance network solution that furnishes multidimensional security. Broadband capable VPN firewall comes with connection insurance: a built-in serial port for dial-up access. This hardware firewall provides greater protection to the network from outside threats.
The HP ProLiant ML 115 G5 is a perfect server for the growing businesses. Designed with SMB (Server Message Block) needs in mind, this product offers expandability through multiple PCI-Express slots, and four hard disk drive capacities. This server has the ability to automatically backup vital information.
These ultra high performance gigabit Ethernet patch cables are perfect for connecting PCs in areas where space is tight. With all the reliability and performance of a standard Cat 5e patch cable, this 1.2mm thick cable is able to fit into even the tightest space and give a neater, less cluttered appearance to desktop or wall jacks.
Fedora is a Linux-based operating system that showcases the latest free and open source software. Fedora is always free for anyone to use, modify, and distribute. It is built by people across the globe. Therefore this operating system is less vulnerable for threats and supports for many platforms. This is a good alternative for cost effective networking systems. This OS has many networking features that supports for reliable network communication.
The NetGear ProSafe VPN client software provides secure network access for remote users and mobile workforce requiring connectivity to corporate network resources. This VPN client software is ideal for customers using NetGear wireless and wired VPN/Firewall routers. NetGear VPN Client supports for all windows platforms and it is easy to configure and deploy. And also this software is cost effective and provides broad security support with the interoperable with IPSec VPN solutions with other major manufacturers. I recommend this product for client computers which have Windows platform. The AVG Anti-Virus SBS Edition gives advanced antivirus software to guard Microsoft Windows server network with maximum spyware protection. It has the ability to protect the system from viruses, Trojans, worms, spyware, adware, and simultaneously scans files, email and internet traffic. The Web Shield and LinkScanner technologies keep network safe from malicious websites and hackers. I recommend this software product for the client computers which mainly have Windows Platform.
As in software development, the network implementation mechanism also has a procedure of implementation. Network Design, Implementation, Testing and Maintenance are the abstract level steps that should be followed in order to implement a complete and well functional network. Before implementing a network, we should design a proper schedule with all the facts. The following schedule is the one that I consider when I’m going to implement a network as a networking advisor.
ISP who plans to offer VPN services has many responsibilities. As the customer has a responsibility upon the enterprise network, ISP has a responsibility upon giving connection and services. ISP should provide installation and support services for their all customers. Following are some services and responsibilities of an ISP.
Prepare a short report on Network Security covering:
A computer network is an interconnected group of computing nodes that is used to share information and other resources (such as printers, scanners and etc) according to a well defined set of rules and conventions known as Protocols. The interconnectivity of the computers reduces the network security and increases the vulnerability. Because, when a computer is uncovered to the public network (or internet), unauthorized access and other malicious software attacks can be occurred from the outsiders. That is why the need of network security is occurred. Network security means understanding the risks, deciding how much risk is acceptable, and gets necessary measures to avoid the risk. Different levels of security are appropriate for different organizations. It varies from one another according to their purposes and rules. No network is 100 percent secure and we can’t even aim for that level of protection. We all know the advantages of computer networks and the internet. Connecting our network to the internet provides access to a vast amount of information and allows us to share them with each. Although this nature of the internet creates so many benefits, it also provides unauthorized users and malicious software easy access to numerous targets. This is the most vital and critical situation of internet. Therefore we all have a responsibility to ensure the safety of our networks. The following parts of this task describe some of the network security threats and the measures that can be taken to protect our networks.
When we talk about network security threats, there are mainly two general categories of threats: intentional and unintentional. Unintentional threats can be defined as the threats that are carried out by accidents or ignorance. For instance, accidently spills water on a server and short the circuitry makes the server inoperable is not an intentional action. But purposely poured water on a server in order to make the server inoperable is an intentional action. According to these examples we can get a vivid idea of intentional and unintentional threats. Intentional threats or attacks can be further divided in to two sub categories such as active and passive threats. An active threat attacks to a system directly. Breaking in to a system and change the sensitive data is the best example for an active attack. In contrast, a passive threat doesn’t attack to a system directly. But it observes the actions and the other behaviors carefully and then attacks to the system silently. Looking key presses when typing a password, collect private and confidential information secretly and social engineering techniques are some examples for passive threats. Trojan horses, Worms, Viruses, Hackers, Spyware, Phishing, Zombies, Spam, Macros, IP Spoofing, SYN Flood, Teardrop, DOS(Denial-of-Service), FIN Attacks, Fraggle Attacks, Man in the middle and Session Hijacking are some examples for common network security threats.
According to the legend, the Greek won the Trojan War by hiding in a huge, hollow wooden horse to sneak in to the city of troy. Then they conquered it and won the battle. In today’s computer world, Trojan horse is defined as a malicious security breaking computer program that pretends or masquerades as a beneficial program. Trojan horse virus is a common security threat that yet difficult to remove. Trojan horse viruses are hidden within seemingly useful software programs. When we execute or install the infected software in to a computer, this type of virus will start infecting to the other files in the computer unknowingly. Trojan horse viruses are mainly used for stealing important information from users’ computers. Then they send this information to Internet servers designated by the virus developers. After this process, the developers can gain a level of control over the computer through these Trojan horse viruses. While these things happen, the users will notice that the infected computers become slow and then it can lead to a computer crash. Trojan horse viruses are mainly spread through email attachments and chat software such as Yahoo Messenger and Skype. Once the users open the attachment, the viruses immediately infect the system and carries out the tasks mentioned above.
A computer worm is a self replicating computer program, similar to a computer virus. But it differs from a computer virus because of its ability to run itself. Although a virus needs a host program or a medium to run (because virus code runs as part of another program), a computer worm doesn’t need a host program to spread. But modern computer worms use files to hide inside. Worms have the ability to spread copies of itself or its segments to other computer systems via network connections. Mainly there are two types of worms such as host computer worms and network worms. Host computer worms exist in the computer they run on and use network connections only to copy themselves to other computers. Host computer worms terminates themselves after they send a copy to another host (so that, only one copy of the worm running somewhere on the network at any given moment). These kinds of worms are called “rabbits”. Network worms have several parts or segments. Each segment of the worm executes on different machines and carries out different tasks. And they use the network for several communication purposes. Propagating their segments form one machine to another is their main purpose. The main part of the network worms is called as “octopus” that coordinates the work of the other segments.
A biological virus is a bacterial that makes us sick. It persists within our body and requires something powerful to get rid of it. A computer virus is also very similar to a biological virus in the way they need a host to survive (or a virus needs a medium for its existence). But in the computer world, a virus is a small computer program spreads from one computer to another and interferes to the computer operations. As a biological virus spreads by injecting its DNA into host cell, a computer virus also needs to attach itself to a document or program to infect other computers and programs. Self propagation is the main feature of a computer virus. Just as a biological virus, the way a computer virus infects to a PC depends on its type. Because all computer viruses have their own features and factors that make them unique and dangerous to the health of a computer. Resident Viruses, Direct Action Viruses, Overwrite Viruses, Boot Viruses, Macro Viruses, Directory Viruses, Polymorphic Viruses, File Infectors, Companion Viruses, FAT Viruses, Worms, Trojan Horses and Logic Bombs are some popular examples for different types of viruses. Computer viruses are easily spread through email attachments and instant messages. Therefore we should never open unknown email attachments. And further, viruses are spread through floppy disks, CDs, DVDs, Flash Drives (Pen Drives) and other storage devices. Having a reliable and updated anti-virus software program is the best solution for this virus threat.
Get anti-spyware software protection.
Peoples are the only threats for computer network security. Because computers don’t have the ability to create malicious programs or launch attacks. Only the people can create malicious programs in order to break into other systems with the help of the computers. Like wise, Hackers are unauthorized users who break in to computer systems in order to steal, change or destroy information. They make the path to break into a system by installing malware without our knowledge. Computer hackers have clever tactics, tools and detailed knowledge of computing. Therefore they break into systems and steal our private and confidential information by using their tools and tactics. The subculture that has made around hackers is often referred as computer underground. Some of the people do hacking for learning purposes. Any computer connected to the internet is susceptible for the threats of hackers. These online criminals typically use phishing scams, spam, email or instant messages and fake web sites to deliver dangerous malware to our computers in order compromise our computer security. Hackers can access our information easily if our computers are not protected with a firewall.
In a denial of service attack, an attacker tries to prevent users from accessing information or other services from a particular network by flooding it with unbearable traffic. In other words, by using DOS attacks, attacker attempts to make computer resources unavailable to its users. Therefore the legitimate users cannot access the email, websites, online accounts and other services that are provided by the victimized computer. Usually DOS attacks are launched by computer hackers. When we type a URL of a particular website on the web browser, we are sending a request to the server that the particular web page is stored. Usually a server can process a limited number of requests at once. So that the attackers overload the server with vast number of requests that the server cannot handle. Therefore the server buffer or backlog will overflow and the services it provides will be unavailable to their legitimate users. This is called a Denial of Service. Like viruses, different kinds of DOS attacks are introduced unceasingly by DOS attackers.
Spyware is a type of malware that installed on computers and collect information about users without their knowledge. This installation process is carried out secretly by the spyware program. Sometimes network administrators purposely install spyware programs in order to monitor the other users on the network. As the term spyware suggests that it secretly monitors the user’s computing, its functions go well beyond simple monitoring. Spyware programs are mainly used to collect users’ personal information, such as Internet surfing habits and sites that have been visited frequently. Spyware programs change computer settings, resulting in slow connection speed, different home pages, and loss of internet or functionality of other programs. Unlike viruses and worms, spyware do not have the ability to self replicate. Usually spyware programs are mainly designed for commercial purposes. As I mentioned above, delivery of automatic pop-up advertisements, theft of personal information and monitoring web activities are some functions carried out by spyware for marketing purposes.
Once a company has determined which parts of the company should be protected, then they document a set of rules in order to protect the company assets. These documented set of rules are defined as a security policy. Although a security policy may seem to be an unnecessary set of rules, the benefits far outweigh the work. Because of it protects the Confidentiality, Integrity and Availability of company data.
Acceptable use policy, password policy, backup policy, Remote Access policy, encryption policy, Network Security policy, guest Access policy, confidential Data policy and Mobile Device policy are some examples for policies. Why there should be a Network Security Policy, in place in all the networked companies? When organizations connect their networks to the internet, their private and confidential information also expose to the public. Therefore the possibility of outside threats, such as hackers and malicious software has increased. That’s why the Network Security Policies have been implemented by organizations in order to protect their network resources from the outsiders. Network Security Policy is a documented set of rules for computer network access. Usually this is a complex document that consists of rules for data access, web browsing habits, use of password and encryption, email attachment and more. Network security policies protect the company from outside threats and limit the internal network access from risky employees. Therefore this document is not only a set of rules, but also a guide for the company network protection.
Linux operating system. (2017, Jun 26).
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