Firewall is a networking device provides protection against threads to your network. Basicly, firewalls are softwares or hardwares designed for protecting networks from bad codes, viruses, hackers or spam web sites etc. Generally software firewalls are used for small-sized networks, hardware firewalls are used for large scaled corporate networks. They sit between LAN and WAN and protects the local area against the threads that may come from wide area.
What Is The Purpose Of Using Firewall ?
Firewall’s working logic is basicly accepting or rejecting to a packet. This process is named “packet filtering”. They use a few methods to check the network traffic. Packet filtering is just one of these methods. Other methods are proxy service and stateful inspection. Proxy service is shortly based on receiving the packet after sended to firewall. Stateful inspection is based on comparing the packets. In this method, data packets are compared with the character strings which are configured as a harmful code on firewall’s software. If this match occurs, packets are marked as harmfull and can’t pass through firewall.
Firewall Configuration
Firewalls come with a pre-config as many devices. There are some filtering rules inside of it but administrator can modify these rules surely.Firewall configuration is not so easy surely, but here is the some of filtering methods can be implemented :
- IP Addresses
- Domain Names
- Protocols
- Ports
- Words
Why We Need Firewall Protection ?
Today, network devices are not just under virus thread. Here are the threads that firewalls can protect us against :
- Remote login
- Application backdoors
- Dos (denial of service) attacks
- Smtp Session Hijacking
- Operating system bugs
- Email bombs
- Macros
- Virus
- Spam
- Source rating
- Redirect bombs
Hardware Firewalls :
Hardware firewalls include high level protection for large scale networks. They provide excellent protections for corporates which aims a single protection umbrealla that provides protection many network devices. Because of hardware firewalls are complicated, they are not so cheap and not easy to configure. That requires expertness to configure them.
Software Firewalls :
Software firewalls are used for small scale networks such as a home network. They provide protection for notebooks, small work groups or desktops. Mostly used for broadband access protection.