In order to block unauthorized access, a firewall is used. It is actually a part of a computer system. However, at the same time it does allow for the authorized communications.
Firewall is capable of permitting, denying, encrypting the traffic on computer mainly between different security domains. This can be achieved by firewall on the basis of some rules and criteria. It may be described as a device or a set of devices.
It is possible to implement firewalls in both hardware as well as software. Additionally, a combination of both can also be used. The access of private networks can be prevented with the help of firewalls. This is especially true for the intranets.
The prime objective of this device is to regulate the traffic through the internet and between the computer networks with different trust levels. A firewall’s function within a network is similar to physical firewalls with fire doors in a building construction. In the firewall related to the computing systems, it is used to prevent intrusion into a private network whereas in case of the physical firewalls, the prime objective is to contain and delay the fire due to structural reasons. Packet filter, circuit level gateway, proxy server, and application gateway are some of the different types of firewall techniques.
