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Detail the functions of a firewall.

Detail the functions of a firewall. What are the benefits and limitations of a firewall? Compare hardware and software firewalls.

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Detail the functions of a firewall. What are the benefits and limitations of a firewall? Compare hardware and software firewalls.

A Firewall is a hardware or software device that filters information coming through the internet into a network or computer system. Firewalls are placed at every connection to the internet. For example, in a company, they would be placed at every T1 or fiber line coming into the company. For an individual computer or home network, they would be placed somewhere between the modem and the computer.
Firewalls work by using three methods to control the data traffic entering into the network or computer. A firewall can use more than 1 of these methods.
1) Packet Filtering - Packets, which are small chunks of data, are analyzed. Only packets that pass the criteria of set of filters are permitted through.
a. Packet filtering checks for information such as protocol (TCP, UDP), source IP address and port numbers, Destination IP and port numbers and router interfaces.
b. Rules are set up on the firewall, for example services such as FTP, Telnet etc (services which pose a threat) are denied.
c. Packet filtering comes in 2 flavors:
i. Static - Examines incoming and outgoing packets. It can not check for application requests or keep track of application state information. It can not check whether or not a packet is the first request to an internal server or a response from an external server to an internal client.
ii. Dynamic - Dynamic filtering can track ...

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The expert details the functions of a firewall.

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