In computing, a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted internal network and untrusted external network, such as the Internet.
Firewalls are often categorized as either network firewalls or host-based firewall. Network firewalls filter traffic between two or more networks and run on network hardware. Host-based firewalls run on host computers and control network traffic in and out of those machines.
Firewalls may also be a component of your computer's operating system. For example - Windows Firewall is a Microsoft Windows application that notifies users of any suspicious activity. The Application can detect and block viruses, worms, and hackers from harmful activity.
Looks at each packet entering or leaving the network and accepts or rejects it based on user-defined rules. Packet filtering is fairly effective and transparent to users, but it is difficult to configure. In addition, it is susceptible to IP spoofing.
Applies security mechanisms to specific applications, such as FTP and Telnet servers. This is very effective, but can impose a performance degradation.
It intercepts all messages entering and leaving the network. The proxy server effectively hides the true network addresses.
It applies security mechanisms when a connection is established. Once the connection has been made, packets can flow between the hosts without further checking.
Work by filtering network and Internet traffic based upon the applications or traffic types using specific ports. Next Generation Firewalls (NGFWs) blend the features of a standard firewall with quality of service (QoS) functionalities in order to provide smarter and deeper inspection.
Any criminal activity that uses a computer either as an instrument, target, or a means for perpetuating further crimes comes within the ambit of "cyber crime".
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Read MoreIt's a special area where you can find special questions and answers for CSE students or IT professionals. Also, In this section, we try to explain a topic in a very deep way.