Fundamentals of Computer Systems

 In this unit, we have already learnt that the firewall is only one entry point to your network. Modems, if you allow them to answer incoming calls, can provide an easy means for an attacker to sneak around, your front door (or, firewall). Just as castlesweren't built with moats only in the front, your network needs to be protected at all of its entry points. Secure Modems, DialBack Systems If modem access is to be provided, this should be guarded carefully. The terminal server, or network device that provides dialup access to your network needs to be actively administered, and its logs need to be examined for strange behavior. Its passwords need to be strong not ones that can be guessed. Accounts that aren't actively used should be disabled. In short, it's the easiest way to get into your network from remote: guard it carefully. There are some remote access systems which have the feature of a twopart procedure to establish a connection. The first part is the remote user di...

 Network security is broad domain term which includes many key elements. Let us discuss these elements in brief: a) Firewall As we have discussed in our earlier discussion on the Internet and similar networks, connecting an organization to the Internet provides a twoway flow of traffic. This is clearly undesirable in many organizations, as proprietary information is often displayed freely within a corporate intranet (that is, a TCP/IP network, modeled after the Internet that only works within the organization). In order to provide some level of separation between an organization's intranet and the Internet, firewalls have been deployed. A firewall is simply a group of components that collectively form a barrier between two networks. Firewall systems protect and facilitate your network at a number of levels. They allow email and other applications, such as file transfer protocol (FTP stands for File Transfer Protocol. It is used for copying files between computer systems. FTP server...

There are many strong tools available for securing a computer network. Tools to protect your enterprise network have been evolving for the last two decades, roughly the same amount of time that people have been trying to break into computer networks. These tools can protect a computer network at many levels, and a wellguarded enterprise deploys many different types of security technologies. The most obvious element of security is often times the most easily overlooked: physical security—namely, controlling access to the most sensitive components in your computer network, such as a network administration station or the server room. No amount of planning or expensive equipment will keep your network secure if unauthorized personnel can have access to central administration consoles. Even if a user does not have evil intent, an untrained user may unknowingly provide unauthorized outside access or override certain protective configurations. Let us briefly discuss few of these network secur...

 Small and medium sized businesses use the Internet and networked applications to reach new customers and serve their existing ones more effectively. At the same time, new security threats and legislation puts increased pressure on business networks to be reliable and secure. Business Challenges According to recent studies, security is the biggest challenge facing small and mediumsized businesses. Everchanging security threats from both inside and outside the business network can wreak havoc on business operations, affecting profitability and customer satisfaction. Small and mediumsized businesses must also comply with new regulations and laws created to protect consumer privacy and secure electronic information. Security issues for small and medium – sized businesses are classified into 5 basic categories: Worms and Viruses As per research, Computer worms and viruses remain the most common security threat, with 75 percent of small and medium businesses affected by it.. Worms and v...

 When the term computer security is used, it specifically refers to the security of one computer, although the overall security of each individual computer is required for network security. When the term network security is used, it refers to the security of the network in general. This includes such issues as password security, network sniffing, intrusion detection, firewalls, network structure and so forth. Securing network infrastructure is like securing possible entry points of attacks on a country by deploying appropriate defense. Computer security is more like providing means to protect a single PC against outside intrusion. The former is better and practical to protect the civilians from getting exposed to the attacks. The preventive measures attempt to secure the access to individual computersthe network itselfthereby protecting the computers and other shared resources such as printers, networkattached storage connected by the network. Attacks could be stopped at their entr...

 There are various threats identified for network security. Let us discuss few of them in brief: Viruses: Computer programs written by devious programmers and designed to replicate themselves and infect computers when triggered by a specific event. Viruses reproduce themselves by attaching themselves to other files that the user does not realize are infected. Viruses spread today mainly through Email attachments. The attachment may be a file that is a legitimate file but the virus may be attached as a macro program in the file. An example is a Microsoft word file. These files can contain macro programs which can be run by Microsoft Word. A virus may infect these files as a macro and when they get on the next user's computer, they can infect other files. These virus programs normally take advantage of a security vulnerability of the running application. Viruses can directly affect executable files or Dynamic Link Library (DLL) files that the operating systems and applications use to...