We provide KEK general purpose network to support various kinds of research activities in the field of high-energy physics, material physics, and accelerator physics. Since the end of 20th century, cyber attacks to the network are on an almost daily basis, and attack techniques change rapidly and drastically. In such circumstances, we are constantly facing difficult tradeoff and are required to keep a balance between safety and usability in research activities. While restriction of network services/applications and network monitoring may improve the safety, too much restriction must be avoided and network monitoring should be done with a full consideration.
In this talk, we present our long-term experiences in keeping a balance between safety and usability in KEK research activities. The key points are ensuring traceability and security management in a reasonable manner. We have been operating security devices such as firewalls, intrusion detection system, and vulnerability management system to realize the balance. In addition, CSIRT (Computer Security Incident Response Team) activities and cooperative activities among research organizations are presented.