Firewalls – Different types of firewalls

Okay, so you are confused as to what are firewalls and which kind of firewall software should you use.Firewalls are basically a device which acts as a filter between a protected or “inside” network such as a corporate LAN and a less trustworthy or “outside” network such as the internet.Most of the times, this firewall is run on a dedicated device, the reason, since it acts as the go between, between the internal network and the unprotected external network, performance becomes a major issue.It means the device must not be used for nonfirewall purposes which could degrade the performance.Firewall software usually runs on a propriety or carefully minimized operating system, so that hackers don’t compromise the system.

The basic purpose of this firewall is to keep the “bad” things out of the protected environment. To achieve this, they employ complex security policies which address when a security threat has occurred.For example a firewall may have a security policy to allow only traffic from inside to outside, or vice-versa for security concerns. Or it maybe that only particular IP addresses are allowed to connect to the internal protected network, limiting unauthorized traffic and the like.The main issue is however to realize which security policy meets ones organization or computer.

Most of the time a personal firewall for your home PC will suffice.Although in corporate companies and enterprise businesses, a firewall is installed on a separate PC and kept well isolated from the other computer and having direct access to the outside network, Its not feasible for a home user to put a separate computer for such a purpose.Another good thing is that if you already have a router, wired or wireless, then its pretty good acting as a firewall as well.You don’t need to install a firewall software separately for it, as it acts as a go between, between you and the internet. Routers have port redirection capabilities and NAT also.So you’re are lucky because your router will also serve as a firewall.If any hacker tries to hack using your IP address, he will be able to connect only to the Router installed on your internal network, and since the router is only a device, its extremely difficult and literally impossible to connect to your computer as its on a LAN.

Firewalls are of 5 types:

Packet filtering gateways or screening routers

Stateful inspection firewalls

Application proxies

Guards

Personal firewalls

For home users like you and me, Personal firewalls are the best and feasible option. These are software’s which control the flow of traffic to and from your computer. Just as a network firewall screens incoming and outgoing traffic for that network, a personal firewall screens traffic on a single workstation.

Commercial software’s for Personal firewall include, Norton Personal Firewall(from Symantec), McAfee Personal Firewall, and Zone Alarm(from Zone Labs).