I read papers and had a solid understanding of OVERVIEW OF FIREWALLS A Firewall is basically a security function which prevents our systems from attacks. That is it acts as wall between our system and remote attackers and makes it difficult for attackers to attack. It is set of related programs which is located at network gateway server which protects private networks from any other network users. . It is set of rules that determine whether packets are safe or not. It protects from viruses, worms