What is a Firewall?
– Firewall is considered to be the most important thing when security is the concern.
– Firewalls help us to maintain the security of the network that we are using.
– They work with the primary objective of controlling the outgoing and incoming traffic via analyzation of the data packets and determination of whether to allow them it not.
– All this is done based on some predetermined rule set.
– Firewall of a network serves a bridge between the computer and the internal network to which it belongs after making sure that the opposite network is secure and trustworthy.
– Firewalls can be classified in to 2 categories namely:
1.Software – based and
2. Hardware – based
– Most of the PCs come with operating systems that are inclusive of the software – based firewalls in order to get protection against the threats from the external network i.e., the internet.
– Also, most of the routers are provided with firewall components.
– At the other side there are certain firewalls than have ability to carry out some routing functions.
Characteristics of a Firewall
1. It provides various protection levels based up on where the system is located. When a computer is connected to a network, a security level is applied by the firewall as per the type of the network in use. This is done by default and can be changed using the firewall settings.
2. Protects the wireless networks such as wi – fi: Everyday a number of intrusion attempts are made through wireless networks including wifi. Firewall blocks all these attempts. Whenever a network is tried to be accessed by an intruder, firewall displays a pop – up warning asking your permission to quickly block the attack.
3. Access to internet and other networks: What all among the programs installed on the computer can access the network is specified by the firewall.
4. Protection against intruders: There are many hackers trying to access the information stored on your computer. Firewall keeps all of them at bay.
5. Blocks: You can specify to the firewall for which all programs you want the access to internet to be blocked. Other systems can also be blocked from accessing content on your system.
6. Definition of rules: Rules that specify which connections should be allowed and through which ports are defined through this. One thing that should be kept in mind while configuring the firewall protection is that these rules might affect the way some programs and resources function.
7. All the incoming and outgoing network traffic must compulsorily pass through the firewall. This firewall ensures by implementing a physical blockage for the access to the network but except through the firewall itself. It provides a number of configuration combinations for achieving this.
8. The local security policy defines the authorized traffic that can pass through the firewall. Different types of firewalls might use different security policies.
9. The firewall has the immunity to penetration. A trusted system can only be used that has a secure operating system.
10. Four general techniques are used by firewall for controlling the access and enforcing the security policy
– Service control: Services that can be accessed are determined by this. The traffic is filtered based up on the TCP port number and the IP address. Also, provides proxy software for receiving and interpreting the service requests before they are passed on.
– Direction control: The directions in which the requests are to be sent are determined by this.
– User control: The access to services is controlled by this. However, this is applicable only to the users that lie in the perimeter of the firewall. Further, it is also applicable to the incoming traffic but requires for a more secure authentication technology.
– Behavior control: controls the usage of the particular services. It also performs functions such as filtering the e – mail for spams and so on.