Understanding Firewall - Firewall configuration techniques - Types of firewall

Normally single device is configured for the firewall but some times it comprises of set of devices acting collectively for restricting unauthorized access. They provide shield for the computer system. They are very useful for the users using the DSL modems

How firewall works
Firewalls works automatically when communicating other sources of network such as other client computer, network computers, internet, private networks and remote access devices. They are provided by the software manufacturers such as windows firewall. Firewalls can be used in both hardware and software or combinations. They basically prevent the unauthorized user from entering the private network set ups. When messages are delivered either from sender or receiver, every message passes through the firewall. When message is safe and contains all the required heads then it safely travel to the next device. But when message is doubtful, firewalls block the message and prompt the receiver about the problem. They also tackle the information with different rules and other criteria that does not match the communication network. This is mostly practiced in intranets. They are really important for the high security of data and computer system from remaining safe from unauthorized users and programs.

Firewall configuration techniques
There are various kinds of firewalls techniques that can be used for the configuration of firewalls such as.

Packet filtering.
In packet filtering packets containing message are completely inspected in order to check and sort if some of them does not match the rules defined by the users. this technique has complex configuration but quite effective and remains transparent to the users.

Application /circuit gateways.
Its another firewall technique that restrict the rules and constraints for the specific applications such as FTP, tenet, TCP and UDP connections that are established between devices and networks. They are very effective. Once these kinds of gateways establish connection then no further packet checking is required.

Proxy servers
Proxy server deals with all the messages which enters and leaves the network for any purposes. This technique is effective because proxy servers hide the original network and computer addresses.

Types of firewall
Firewall can be implemented in two types

Hardware firewalls
Hardware firewalls are also known as network firewalls these external devices are configured or placed between the computer system and digital subscriber line to inspect the data. They provide high level protection to the entire communication. It has the advantage over software firewalls that they can be configured separately and operating system can run firewall for every individual device.

Software firewalls.