Basic Security Guide 3
Firewall Software
Here you must distinguish between two different types of firewalls:
*Desktop-Firewalls*
They interpose into the operating system and catch unwanted data packages before they can reach the target program. They also catch data, which is sent from specific programs to the web. You can define rules to block or allow certain programs to be used. You can also define rules to allow or block certain data from being received or sent.
But desktop firewalls have a fundamental weak point. They can be bypassed. Nearly everyone has a rule for the web browser (Internet Explorer) defined, which allows the browser to access the web. This fact is capitalized by some Trojans that hijack the browser to make a connection to outside the computer with the rights of the browser. Another weak point of desktop firewalls is, that they can only catch data that is processed by the communication modules of the operating system (WinSock). If a harmful program uses it's own communication module (it's own protocol stack) the firewall can't do anything against it in most cases. Examples of desktop/software firewall includes Comodo Firewall Pro, and Zonealarm Firewall.
*Hardware Firewalls*
Firewalls that are not installed on the local computer are better in every way. They are located between your computer and the Internet. So they can hardly be bypassed. Hardware firewalls are special appliances or computers with special firewall software installed. For private use, they are too expensive in most cases. But several routers can also be used as hardware firewalls.
The best solution in any case is don't run software that tries to send or receive unwanted data. Don't open unnecessary ports and set the firewall to block them. Examples of hardware firewall cum router is D-Link DI 524 router, and Linksys WRT54G. Router.
Here you must distinguish between two different types of firewalls:
*Desktop-Firewalls*
They interpose into the operating system and catch unwanted data packages before they can reach the target program. They also catch data, which is sent from specific programs to the web. You can define rules to block or allow certain programs to be used. You can also define rules to allow or block certain data from being received or sent.
But desktop firewalls have a fundamental weak point. They can be bypassed. Nearly everyone has a rule for the web browser (Internet Explorer) defined, which allows the browser to access the web. This fact is capitalized by some Trojans that hijack the browser to make a connection to outside the computer with the rights of the browser. Another weak point of desktop firewalls is, that they can only catch data that is processed by the communication modules of the operating system (WinSock). If a harmful program uses it's own communication module (it's own protocol stack) the firewall can't do anything against it in most cases. Examples of desktop/software firewall includes Comodo Firewall Pro, and Zonealarm Firewall.
*Hardware Firewalls*
Firewalls that are not installed on the local computer are better in every way. They are located between your computer and the Internet. So they can hardly be bypassed. Hardware firewalls are special appliances or computers with special firewall software installed. For private use, they are too expensive in most cases. But several routers can also be used as hardware firewalls.
The best solution in any case is don't run software that tries to send or receive unwanted data. Don't open unnecessary ports and set the firewall to block them. Examples of hardware firewall cum router is D-Link DI 524 router, and Linksys WRT54G. Router.
posted by Ernest at
4:58 AM
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