This article states the use of firewall for your security of your operating system from unwanted browsing sites .The firewall plays a vital role in maintaining security of your assets on computer. Have you ever noticed when u type domain www.facebook.com in your college, company or institute it is not available to intended user WHY the reason is administrator has hosted firewall for security.
A firewall protects networked computers from intentional hostile intrusion that could compromise confidentially or result in data corruption or denial service .It may be a hardware device or a software program running on a secure host computer. In either case, it must have at least two network interfaces, one for the network it is intended to protect, and one for the network it is exposed to.
A firewalls sits at the junction point or gateway between the two networks, usually a private network and a public network such as internet .The earliest firewalls were simply routers .The term firewall comes from the fact that by segmenting a network into different physical sub networks, they limited the damage that could spread from one subnet to another just like fire doors or firewalls.
What Does a Firewall Do?
A firewall examines all traffic routed between the networks, otherwise it is stopped .A firewall filters both inbound and outbound traffic .it can also manage public access to private networked resources such as host applications. It can be used to log all attempts to enter the private network and trigger alarms when hostile or unauthorized entry is attempted.
Firewalls can filter packets on their source and destination addresses and port numbers. This is known as address filtering .Firewalls can also filter specific types of network traffic. This is also known as protocol filtering because the decision to forward or reject traffic is dependent upon the protocol used, for example HTTP, FTP or Telnet. Firewalls can also filter traffic by packet attribute or state.
What Can Firewall Do?
A firewall cannot prevent individual user with modems from dialing into or out of the network, by the passing the firewall altogether. Employee misconduct or careleness cannot be controlled by the firewalls .Policies involving the use and misuse of passwords and user accounts must be strictly enforced these are management issues that should be raised during the planning of any security policy but that cannot be solved with firewalls alone.
Who Needs Firewall?
Anyone who is responsible for a private network that is connected to a public network needs firewall protection. Furthermore, anyone who connects so much as single computer to the internet via modem should have personal firewall software.
How Does a Firewall Works?
There are two access denial methodologies used by firewall.
A firewall may allow traffic unless it meets certain criteria, the type of criteria, or it may deny all traffic unless it meets certain criteria .The type of criteria used to determine whether traffic should be allowed through varies from one type of firewall to another .Firewalls may be concerned with the type of traffic, or source or destination addresses and ports. They may also use complex rule bases that analyses the application data to determine what traffic to let through depends on which network layer it operates at
Benefits of Firewall
1. Firewall protect private local area network from hostile intrusion from the internet
2. Consequently, many LANS are now connected to the internet where internet connectivity world otherwise have been too great risk.
3. Firewalls allow network administrator to offer access to specific types of internet services to selected LAN users
4. Privileges can be granted according to job description and need rather than on all or nothing basis.