ISO/IEC 18028-3:2005 provides an overview of security gateways through a description of different architectures. It outlines the techniques for security gateways to analyse network traffic. The techniques discussed are as follows: packet filtering, stateful packet inspection, application proxy, network address translation, content analysing and filtering. Additionally, ISO/IEC 18028-3:2005 provides guidelines for the selection and configuration of security gateways. It gives guidance to choose the right type of architecture for a security gateway, which best meets the security requirements of an organization.