In this paper, the authors discusses about basics of network security. The paper starts with the introduction to network security problem and then it analyzes the computer network security features and the main threats to the network security. After that solutions to the network security problem are discussed. In actual there are very large number of solutions exists but they have discussed mainly three solutions namely firewall technologies, the intrusion detection and prevention technology. And in the end of this paper they have discussed the integration technique which can be used to integrate different techniques to improve the real-time check, accuracy and recovery ability of the network security system.