Basics of Firewall

what is a firewall?

There are two categories of firewalls available on your requirement. 

1. Software Firewalls (Program)

2. Hardware Firewalls (Appliance)

Basically, Firewall can use to control access among the network as well as from external access in a proper manner. Moreover it can control the network traffic and provide secure network to the end user. Further, firewall can use to control access data,control application and prevent from viruses in the gateway level. That means, you can block viruses before they execute in your network and from the gateway level you can delete these viruses. 

Insecure Network

without having a proper firewall, you will not be able to achieve a secure network. Insecure network gives you lots of troubles such as information hacking , information loosing and low performance of your internal network. This scenario leads to unsatisfactory and you will not be able to give the priority to your mission critical application in your organization.

Software Firewalls
1. IP Tables
2. ISA
3. Zone Alarm

Hardware Firewalls
1. Watchguard
2. Juniper
3. Fortigate
4. Check Point
5. Cisco

 There are several buying factors available to consider, when you buy a firewall to your organization. Not only the brand name there are several factors available. But when you consider all the firewall models, they are having same technology and techniques. But vary from features available.

Buying Factors of a Firewall

1. Firewall throughput
2. VPN Throughput
3. Concurrent Sessions per second
4. No of Interfaces
5. AV (Antivirus) Throughput
6. UTM throughput

Firewall Throughput
Most of the time, we have to consider about the firewall throughput according to our requirement. Moreover, number of users in the network and user application and number of external links also to be consider. Considering the number of users in the network, need to go for a firewall with reasonable throughput.

VPN Throughput
Number of VPN users also needed to be consider when you going to purchase a firewall. Because number of VPN connection is depend on  the VPN throughput .

Concurrent Sessions Per Second
This is also needed to be consider , because number of users ans their usage is depend on number of concurrent sessions which can handle by the firewall.

Number of Interfaces
You must concern on your infrastructure , before you buy the firewall. Because there are limitation on number of external interfaces available. So this must be a critical factor, when you going to buy a firewall.

AV Throughput
Antivirus throughput also needed to consider , because this is a gateway level antivirus and therefore we can prevent from viruses. If you have a proper gateway level antivirus, end user level protection is not that much big problem. I am not going to say that you should not go for a desktop protection. You should go for desktop protection. But up to some extent , you will be protected with gateway antivirus solution.


Basic Firewall Configuration

 Here we discussed about basic network infrastructure with a fire wall. There are few methods available to configure your firewall according to your requirement.

1. Mixed Routing Mode - All the interfaces are in different networks.

2. Drop-In-Mode - All the interfaces are having same IP address
3. Bridge Mode - (Transparent Mode) All the interfaces are in same network but can assign different IPs.


Mixed Routing Mode