Do you know what a firewall is? How does it protect our system? It is a network security system which is used to control the incoming and outgoing network traffic. A firewall is established between a secure and trusted internal network and another network that is assumed to be not secured and trusted. Firewalls protect your system form harmful software that may come to attack your system or from prying hackers. Also firewalls ensure safety and protection to your system.
Usually firewalls exist both as software and hardware. The hardware based firewalls also offer other functionality to the internal network that they protect, such as acting as DHCP server for that network. But an ideal firewall is a combination of both hardware and software. A firewall can not only provide limiting access to your computer and network, but can also allow remote access to a private network through secure authentication certificates and logins.
Hardware firewalls can be purchased as a stand-alone product. They are typically found in broadband routers, and are also considered as an important part of the system and network set-up. These types of firewall have a minimum of four ports. The other type of firewalls, the software firewalls can be installed on your computer and you can customize it. We can control its function and protection features. This type of firewall will protect your computer from outside attempts to gain control or access .
Now let us see the common firewall techniques:
In this method, the server looks at each packet entering or leaving the network and accepts or rejects the packets based on some user defined rules. This technique is effective and transparent to users, but is difficult to configure. Mostly, it is susceptible to IP spoofing.
In this technique the security mechanism is applied to specific applications, such as FTP and Telnet servers. This technique is very effective, but it may sometimes impose performance degradation.
This technique applies a security mechanism to the server when a TCP or UDP connection is established. Once the connection has been established, the packets will flow between the hosts without additional checking.
This technique intercepts all the messages that are entering and leaving the network. The proxy server will hide the true network address.
Most of the firewalls will use two or more of the above techniques in concert. A firewall may be considered as the first line of defense against unsecured data. If you want more security, a method called data encryption can be used. Firewalls may be hardware devices or software programs. They filter the traffic that flows into your website or PC by the means of an internet connection. The firewalls will continuously monitor the data flow to your computer and if any harmful data is detected, they will block it.0