Internet Firewalls for Trusted Systems

A firewall is a device or group of devices that controls access between networks. It is a security gateway that controls access between the public Internet and an intranet and is a secure computer system placed between a trusted network and an untrusted Internet. Firewalls can be classified into packet filters, circuit‐level gateways, and application‐level gateways. The primary step in designing a secure firewall is obviously to prevent the firewall devices from being compromised by threats. To provide a certain level of security, a single‐homed bastion host, a dual‐homed bastion host, and a screened subnet firewall are considered. From firewalls to intrusion detection systems (IDSs), information technology (IT) industry's security solutions have been progressed effectively in some extent for preserving data integrity, protecting data confidentiality, and maintaining data availability. This chapter presents a survey and comparison of Internet worm/virus detection against cyber defense.