What is a Network Firewall?

Well, along with final year project , reading some Islamic books, I am also touching a book name “CISCO NETWORK SECURITY By James Pike”.  As I am going through this book , learning so many things about the network security issues , challenges, counter measures and so on . Specially related to the equipment by Cisco which is worlds’ biggest vendor of the network equipment. So many from the contents list , In this blog I am writing about he Firewalls.

So what is basically a Firewall?

The term is borrowed from building construction in which a wall is placed or reinforced to prevent the spread of the fire , usually fabricated from bricks , stones, or some highly fire-resistant material. The term has also been used differently in networking. in early 1990s, the term was used when referring to routers , since they would effectively block broadcast storms that were common on the large bridge networks. Bridges and switches always forward broadcast by default , unless the filters are applied.

Now a simple  , broad definition is : ” a firewall is a device or a system of devices that enforces an organization’s access control policy between two or more different networks”. This a broad definition this can also construed as , a router with simple access list, a PC with a appropriate filtering software a host a group of hosts collectively .

Protection and Features a Firewall can provide.
  • Vulnerable applications or services are protected from attacks , and can be used inside your network.
  • controlled access into your site- network administrator can control the traffic entering in your site.
  • observation of all the traffic entering and exiting your network.
  • isolation from semi public resources by creating separate security zones.
  • maintain the privacy of the network infrastructure.
  • audit trail and statistics
  • confidentiality , integrity and authenticity .
  • advanced authentication
  • prohibits access to inappropriate sites by your users

I hope you got at least a bit of information from this blog.

Well in the next blog I will discuss what a firewall doesn’t protect against and Firewall architecture.


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