A firewall is a network device used to block certain types of network traffic. Basically, a firewall forms the barrier between a trusted and an untrusted network.
A firewall can be a hardware, software, or a combination of both. It is used to prevent unauthorized programs or Internet users from accessing a private network and/or a single computer
A firewall focuses on implementing your security decisions for compliance purposes. It can stop hackers from accessing your computer with the packet filtering function. it enforces security policies by filtering wanted and unwanted traffic. A firewall Protects your personal information and limits data exposure from unauthorized access. Firewalls also Blocks “pop up” ads and certain cookies. It can also determine which programs can access the Internet.