Hello everyone I here again. Today I am going to describe about firewall. It is a common question which I answered to my friend or users about firewall. So today I’ll explain about firewall. Whenever you work on internet in office/home/school you always listen about firewall. Yes of course some of us always complain about it also, well-well that’s the other side of the coin. In this and upcoming post I’ll describe about firewall and how its work.
Firewall is basically kind of roadblock to keep unwanted/insecure force away from your own area. The job a firewall is very similar to physical firewall that keeps fire from spreading from one place to another.
A firewall is a software or hardware that filters information pass through the internet into our LAN or computer system. If accessed information packet is marked by filters, it is not allowed through the network.
One example I would like to give to better understand the concept the Firewall. Suppose you have 200 employees with the internet connection to all with no firewall in network. All the computers don’t have any restrictions over the internet. Employees accessing public mails/Accessing LAN FTP over internet without any restrictions. In this case hackers have 100% freedom to enter in your network and they can fully control your network, they can easily still company’s important data.
In apposite case if this company installed firewall with limited rights to access internet. They can access only that service what is permitted to them. Suppose an employee need to access FTP service, so in that case this service can be permitted to that employee only not to everyone.
Methods using by Firewalls: Every firewall use one or more three methods to control traffic flowing in and out of the network –
• Packet Filtering: Packets (small piece of data) are analyzed against a set of filters. Packets that make it through the filters are sent to the requesting system and all others are discarded.
• Proxy Service: Information from the internet is retrieved by the firewall and then sent to the requesting system and vice versa.
• Stateful Inspection: A newer method that doesn’t examine the contents of each packet but instead of this compares certain key parts of the packet to a database of trusted information. Information traveling from inside the firewall to the outside is monitored for specific defining characteristics, and then incoming information is compared to these characteristics. If the comparison yields a reasonable match, the information is allowed through. Otherwise it is discarded. In next post we will talk about Firewall configuration/ and why firewall is secure to protect our network.
A firewall is a software or hardware that filters information pass through the internet into our LAN or computer system. If accessed information packet is marked by filters, it is not allowed through the network.
One example I would like to give to better understand the concept the Firewall. Suppose you have 200 employees with the internet connection to all with no firewall in network. All the computers don’t have any restrictions over the internet. Employees accessing public mails/Accessing LAN FTP over internet without any restrictions. In this case hackers have 100% freedom to enter in your network and they can fully control your network, they can easily still company’s important data.
In apposite case if this company installed firewall with limited rights to access internet. They can access only that service what is permitted to them. Suppose an employee need to access FTP service, so in that case this service can be permitted to that employee only not to everyone.
Methods using by Firewalls: Every firewall use one or more three methods to control traffic flowing in and out of the network –
• Packet Filtering: Packets (small piece of data) are analyzed against a set of filters. Packets that make it through the filters are sent to the requesting system and all others are discarded.
• Proxy Service: Information from the internet is retrieved by the firewall and then sent to the requesting system and vice versa.
• Stateful Inspection: A newer method that doesn’t examine the contents of each packet but instead of this compares certain key parts of the packet to a database of trusted information. Information traveling from inside the firewall to the outside is monitored for specific defining characteristics, and then incoming information is compared to these characteristics. If the comparison yields a reasonable match, the information is allowed through. Otherwise it is discarded. In next post we will talk about Firewall configuration/ and why firewall is secure to protect our network.
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