A firewall
protects your entire IT infrastructure from unwanted access from the Internet. For this purpose, the firewall checks which data is downloaded from or uploaded to the Internet. This includes in particular data transfers that run in the background and are not visible to the user. A firewall also protects against hacker attacks, blocks malware such as trojans, viruses and worms, and ensures secure Internet access.
Antivirus protection is absolutely necessary, even if a powerful firewall is installed. A firewall only protects against access via the Internet and not against infections of a PC via a data carrier. Should a virus nevertheless find its way onto a device, e.g. via an infected USB stick, an antivirus program protects against infection and spreading on your PC or network.