This part of ISO/IEC 27033 gives guidance for securing communications between networks using security gateways (firewall, application firewall, Intrusion Protection System, etc.) in accordance with a documented information security policy of the security gateways, including:a) identifying and analysing network security threats associated with security gateways;b) defining network security requirements for security gateways based on threat analysis;c) using techniques for design and implementation to address the threats and control aspects associated with typical network scenarios; andd) addressing issues associated with implementing, operating, monitoring and reviewing network security gateway controls.