Firewall Crash Course Part – I ( Whats a firewall??)


                              Knowledge expands our perception of the universe.

ALERT: Basic network terms maybe linked to wikipedia or other sources.



So, What’s a firewall??

Wikipedia defines firewall as :-  A network security system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted, secure internal network and another outside network, such as the Internet, that is assumed not to be secure or trusted.

Lets make learning easier with an example:- Suppose you have 3-4 systems connected in a LAN . These Systems are connected to internet through a simple system working as a server . One of the systems in your network hosts a file server for your family members to download photos/videos/files. U have guests at your home who need internet access.So, how do u prevent them from accessing into your private files while allowing your family to do so? Here’s where firewall comes in, u set up a firewall in your system that’s acting as your server and write rules(we will see about it soon) such that only the systems that your family uses have access to it (here systems 1 and 2) as shown in FIG.1.

Note:- Firewall can also be used for a single system for purposes like blocking a malicious program from stealing your personal data and sending it to its server.


new-bitmap-image                                                                            FIG.1


So, lets divide the  systems here into 2 parts here ( This is the basic preparation before writing rules)

Trusted ( system 1, system 2, file sharing system)

Not trusted ( any incoming traffic through the router that is not trusted list mentioned above




In part 2(coming soon), we will be exploring windows firewall(built in) and then download a free firewall and look at the options it provides to  us and try blocking specific ports/programs from accessing internet.

Any query(s)/doubt(s)/suggestion(s) can be notified using the comment session below to which our admins/authors will answer.

Looking forward to hear from you . 


4 thoughts on “Firewall Crash Course Part – I ( Whats a firewall??)

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s