In computer networks, a firewall is software or hardware that controls incoming and outgoing network traffic by filtering out unwanted applications and content. A firewall is designed to prevent unauthorized access to an organization's computer networks and protect data and applications from malicious threats. A firewall can also provide security measures that prevent users from damaging their own systems or those of their organization.
Many people have firewalls set up on their home computers so that no one can access their computer without permission. They can also protect their cell phones and computers from the viruses that are spread on the Internet. The firewall can be installed on the PC or on the router itself.
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