What are the functions of a firewall

The firewall - your doorman between the computer and the network

  • Access rights of external IP addresses: Attempts to access other computers in the network are identified using the IP address and are initially blocked by default. If data exchange is desired, you can allow it manually or add the IP address as an exception so that next time you can access it without a query.
     
  • Access queries from online programs: Manual confirmation should also be set when installing programs that are made available online. In this way, you can be sure that you are actually installing the file you want, and you can immediately see if an untrustworthy website tries to infect your computer with malware.
     
  • Visibility in networks: You can set the visibility of your computer in networks. It is recommended to hide the computer in public networks (e.g. WLAN hotspots at airports or in caf├ęs) and thus additionally protect it from attempted access. Even if visibility is not the same as access authorization, it does mean that malefactors have an easier time targeting your data.
     
  • Blocking active website content: Some technologies for displaying dynamic website content (videos, animated graphics), e.g. Microsoft ActiveX or Adobe Flash, for example, are repeatedly misused to spread malware because the content is executed locally on the user's computer. It is possible to block the execution of this content from the outset.

These are just some of the settings that you can make in the software configuration of your firewall. Of course, you can not only block websites, services and IP addresses, but also classify them as trustworthy and thus allow automatic access. This is how you can recognize them Limits of a firewall - To ensure that malware is reliably fended off, you must correctly assess the access by programs and other computers.

Because of this, it is important that you not only rely on the firewall, but rely on it use a reliable antivirus program at the same timethat compares both installed programs and dynamic website content with current virus definitions and blocks them if necessary or warns them before they are executed.

Many firewalls also work with ports. In order for a data packet from the Internet to reach your own computer, it has to pass through such an input. Each application uses a specific port. A firewall can be set so that only ports that are really needed are opened can. The firewall blocks all other inputs and thus prevents applications from receiving unintentional or unplanned data packets. This technique regularly leads to programs not working due to the firewall. In such a case, the firewall should not be turned off, but only the required port should be released.