These shield your computer or network from malicious or unnecessary network traffic and prevent malware from accessing the network. Firewalls may be broadly categorized as hardware or software.
Hardware, a.k.a. network firewalls, are external devices positioned between a computer and the internet. Many vendors and some ISPs offer integrated small office/home office routers that also include firewall features. Hardware-based firewalls are particularly useful for protecting multiple computers.
Most operating systems include a built-in firewall feature that should be enabled. Firewall software can also be obtained from a local computer store, software vendor or ISP. If downloading firewall software from the internet, make sure it’s from a reputable source and offered via a secure site.
Firewalls primarily help protect against malicious traffic and not against malware, and may not protect the device if you accidentally install malware.