How Does a Firewall Work

I herd that firewall is use to protect the network I want to know how it work . where it is available ? how many types of firewall is exist and who can have a firewall . and how to protect our computers system with the help of firewall ??

yes you rite the function of firewall is basically to protects internet networked system from intended antagonistic invasion that can effect in information or data corruption or failed or internet service. Firewall can be a hardware device or a software program that performs operation for a secure computer.it should have at a minimum of 2 network interface, first one is for network that what we need to protect, and second for the network it is uncovered to the network .A firewall sits at connection end among the both networks, typically for confidential network and a open network like Internet. The most basic firewalls was a simple router.

firewall is nothing it is just a system planned to avoid illegal access to private internet network. Firewalls can be used as both hardware and software, or also as a arrangement of both.

Firewall are divided into different types :-
• Packet filter: that only allows or restrict the network at packet level.
•Application gateway: it is implemented only in applications level like Telnet and FTP servers.
• Circuit-level gateway: implemented when there is a UDP or TCP network connection is establish.
•Proxy server: it is combination of all firewall that filters data at the all level including packets level and leaving the network. It also hides the network address.

A firewall is a collection of associated program, situated in a network ,that protect the assets of a secret network from users of another networks. Fundamentally a firewall is acting same as router, checks each and every network or data packet and decides that is should allows for the network or not. A firewall also work same as proxy server.A firewall is regularly installed in a particularly selected computer in order to take apart from the rest of network in that case no incoming demand can acquire at confidential network resources. There are a lots of firewall transmission methods.

anybody who have authority to have a private or confidential network that is linked to a open network requires a firewall protection. Person who connect with a solo computer system to Internet must have a own firewall some of users feels that no malicious trespasser could be break into computer system. Firewalls frequently have NAT functions with them, and the hosts computer system is protected at the back at a firewall usually got addresses in the confidential address range, Firewalls often got such functionality to cover the IP address of confined computer hosts.

A firewall is generally a gadget or group of devices combined to allow or restrict network for packet transmission depends on a set of regulation and firewall is often used to protect the networks from illegal access at the same time allowing legal packets to enter .
• Firewall is a protection system that increase the level of security among your computer system and the internet network .
• Firewall is use to avoid viruses to go through in your computer system.
• The most useful and significant step what you can take is to defend your system is to switch on firewall.
• If any one of the system got infected, firewall on every computer system assist to avoid the virus that gets into your network
• Use of firewall is vital it does not matters that how you attach to the internet network with the help of a dial- up modem or cable connection or DSL.