Firewall - Definition and Detail of Firewall

Firewall

Firewall is network security system which is used to control and monitor the incoming and outgoing traffic of network with the help of rules defined in it. Firewall is basically used to built a hurdle between secure and trusted network which is also known as internal network with other network or know trusted/ secure network. Firewall are both in hardware and software forms. The main difference between them is the difference in feature and functionality of firewall. Some hardware firewalls offer other functionality such as act like DHCP server for the network to which they are protecting.

Personal computer operating system has software based firewall which protect them form threats coming from other network such as internet. Many routers which exchange data between different networks contains firewall component and same as firewalls perform basic functions of routing.

CLICK HERE TO DOWNLOAD

PDF FILE

Hardware and Software Firewall

There are both type of firewalls which are hardware and software but the configuration of ideal firewall consists of both hardware and software. Limiting access to personal computer and network, firewall is very useful for remote access to private network using certificates of secure authentication and logins.

Hardware Firewalls

Standalone hardware firewall product can be purchased but they are also found in broadband routers and considered as an important part of personal computer and network setup. Hardware firewall have four minimum number of network ports to connect personal computers with it, but for enterprise networks, networking firewall enterprise solutions are available.

Software Firewalls

Software firewalls are installed on personal computers like any other software and can be customized by allowing limited control to some functions and protection features. Software firewall basically provide protection against attempts to control or to gain access to personal computer form outside.

CLICK HERE TO DOWNLOAD

PDF FILE

History of Firewalls

The term firewall basically refer to a wall having fire on it. Firewall technology comes in late 1980's when internet is new technology in its global use and connectivity terms. The predecessors for network security with firewall were routers which are used in late 1980's.

Types of Firewall

There are five type of Firewalls

1. Packet Firewalls
2. Stateful Firewalls
3. Application Layer Firewalls
4. Proxy Firewalls
5. Network Address Translation Firewalls

Packet Firewalls

In early stages firewalls work as packet filters, by examining the each packet that is transferred form computer to the internet. When packet is traveled from packet filter firewall, it checks its source and destination addresses, its protocol type and the port number of destination against the set of rules defined in it.

Stateful Firewalls

To check the connection state of packet there is a need of firewall to record the state of all the packets which passed through it. Firewall ensures, that packet has enough information to estimate that whether a packet is start of new connection, existing connection part or not a part of any connection. This process is known as "STATEFUL PACKET EXAMINATION" and it was introduced in 1994 with the name of check point software in FireWall-1 Software Firewall and after that late in 1990's it was common feature of firewall products.

CLICK HERE TO DOWNLOAD

PDF FILE

Application Layer Firewalls

As the increasing number of attacks on web servers there is the need of firewall which protect both servers and applications which are running on servers. Application layer firewall technology first comes in 1999, which examines and filter the packets on any layer of OSI model up to application layer.

The major benefit behind the filtering of application layer is to block specific contents such as introduced malware or some suspicious websites, and recognize the misuse of some protocols and applications such as HTTP, FTP an DNS.

Proxy Firewalls

Proxy Server Firewalls are operated at application layer of firewalls which act as intermediate for the requests coming from one network to another network for some specific application. These firewalls prevent the direct connection from both sides of firewall and both sides are forced to establish the connection via proxy which can allow or block the traffic using the set of rules defined in it.

Network Address Translation Firewalls

Some firewalls have the functionality of NAT (Network Address Translation) and the hosts which are protected behind the firewall are commonly assigned ip address for private ip address range. Some firewalls have the functionality of hiding the original ip address of the hosts protected by them. Basically functionality of NAT was developed to address limited rout-able addresses of IPV4 which are assigned or used by different companies or personal computers and as well as to reduce the amount of purchasing enough amount of public addresses for each computer working in organization. Hiding the addresses of devices which are protected by firewalls has become increasingly important defense against reconnaissance attack on networks.

CLICK HERE TO DOWNLOAD

PDF FILE