What is a firewall used for?

Answer 1

A firewall is usually placed in front of a group of machines and its primary function is to control communication from and to this group of machines. Communication between two machines over the internet is a stream of packets (datagrams) send in both directions. The firewall examines all packets that is about to be routed through the machine and, based on a set of rules, determines if the packet is allowed to pass through the machine or not. This functionality is often referred as a packet filter.

The secondary function of a firewall is to modify the packets passing through the firewall. This is called Network address translation (NAT), as the modifications usually applies to either sender or receiver information contained in the packets. NAT can for example be used to allow machines without a public addressable Internet protocol (IP) number, to access the Internet through a firewall, by using the IP-number of the firewall as the sender identification. This is also called ip masquerading, as it disguises the address of the machines behind the firewall.

www.goldstardailynews.com

Answer 2

Firewall is basically used to prevent the network from unauthorized access. These are basically of 2 types: 1) Hardware Firewall:-Its works on network layer and used for packet filtering usually used for network security. Its only allow/deny packets(ports). eg- Cisco pix, checkpoint , juniper etc. are vendors of H/W firewall. 2) Software Firewall:- Its work at application level.It is signature based firewall it does not blocks malicious packets. Its only blocks predefined malicious signature. eg- Antivirus like Mcafee, Symantech, Quick Heal

Answer 3

Purpose of firewall is as follows: Firewalls are used to mediate and control all information that is communicated between an external (untrusted) network and an internal (trusted) network. They make use of IP filtering and application proxies to implement firewall security policies.

Answer 4

these are part of Google, used to a letest version, used i internet sever machine and experiment to many task define

Answer 5

Security firewall is used for preventing unauthorized access to or from a private network. Firewalls can be both implemented in softwares and hardwares.