In this paper, we focus on the design and building of iDNS-MS by using knowledge-based system and ontological engineering technologies. iDNS-MS, developed by using web interface and expert system technology, is a unifying environment for providing plausible answers to help solve the complex DNS management problems or alleviate these DNS administration loadings. In iDNS-MS, we propose an ontology-driven model to elicit rules from a previously built DNS ontology and construct an objected-oriented knowledge base. The whole process of the model consists of ontology construction, knowledge class organization and facts/rules loading phases. Ontology construction phase is used to construct the domain ontology, knowledge class organization phase is used to organize the relationships between the knowledge classes, and facts/rules loading phase is used to fill in the facts/rules of knowledge classes extracted from domain experts. In addition, we adopt DRAMA/NORM development environment as the expert system shell to design and implement a unifying framework (e.g. DNS-related problem diagnosis, planning, tutoring, etc.) for supporting intelligent DNS management. According to our experimental results, the paradigm of using DNS ontology to build iDNS-MS works good and effective. iDNS-MS will benefit the sharing and reusing of global DNS knowledge, the reduction of people's time to learn DNS management, the ease of DNS configuration and planning, and the improvement on DNS and network operation.