Firewall - Part 2

Firewall had undergone lot of changes with added services, today let us see the generation of firewalls and its futures.

First generation firewall:

First generation firewall is a packet filter firewall, it will check network addresses and ports of the packet to decide, weather the packet should be blocked or allowed.

Packets are on the layer 3, which means most of the networks are done between physical and network layers, it will inspect the traffic flow and check weather to block or allow the traffic. For example, if the rule in the firewall for blocking telnet it will filter the port number 23 to block the traffic.

Second generation firewall:

It’s a state full firewall, second generation firewall perform the work of same first generation firewall, but operate on transport layer. It will keep the packet until enough information is made to judge about it state, this process is known as state full inspection.

Third generation or Next- generation firewall:

The main success of the firewall is application layer filtering, means it can understand certain application and its protocols such FTP, DNS, HTTP.

It’s also called as next generation firewall after 2012 itself.

Based on its services and its evaluation, firewall is divided into four types

·         Static Packet filtering firewall
·         Application level gateway firewall or Proxy firewall
·         Circuit level gateway firewall
·         Stateful inspection firewall