TERENA The purpose of the Incident Object Description and Exchange Format is to define a common data format for describing and exchanging incident information between collaborating Computer Security Incident Response Teams (CSIRTs). The specific goals and requirements of the IODEF are described in [2]. One of the design principles in the IODEF is compatibility with the Intrusion Detection Message Exchange Format (IDMEF) [3] developed for intrusion detection systems. For this reason, IODEF is heavily based on the IDMEF and provides upward compatibility with it.