Browsing by Author "Liu, CL"

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A distributed intrusion detection model for the domain name system
(2002-11-01)
Chen, CS
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Tseng, SS
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Liu, CL
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資訊工程學系
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Department of Computer Science
We have investigated the problem of detecting DoS-like DNS anomalies in DNS system. In this paper, we propose a distributed Two-phase DNS anomaly detection model for solving the problem. Three sets of algorithms corresponding to different configurations are proposed, including one sequential algorithm and two distributed algorithms, each with an increasing level of parallelism. The complexity of these algorithms have been found to be O (n l(og)n). The distributed algorithms show at least a constant (1-1/C-k), C-k > 1, improvement over the sequential one. To evaluate the performance, we have implemented the algorithms and applied them to a number of examples. The experimental result shows a speed up of about 1.68 on the test example for running on an enhanced distributed architecture with C-IDS over the sequential one. A higher speedup might be common because DNS anomalies will make the traffic distribution more concentrated on the outliers, and the computation will usually converge much more quickly.
A unifying framework for intelligent DNS management
(2003-04-01)
Chen, CS
;
Tseng, SS
;
Liu, CL
;
資訊技術服務中心
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Information Technology Services Center
The Domain Name System (DNS) is a special kind of distributed directory service for people to create and access the network information systems by (1) allowing local control of its segments and (2) making each segment's data available on the Internet using a client-server scheme. However, few administrators have the expertise to do the jobs well since this distributed mechanism is a double-edged sword; it allows DNS not only to scale to Internet size but also allows for incredible mis-configurations. The presented study is an analysis of what problems and difficulties most DNS administrators might encounter and provides the insights into how various DNS assistant sub-systems could be designed and deployed to solve the complex problems or alleviate these DNS administration job loadings. Ontologies become an important mechanism to build information systems. The role of ontologies is to capture domain knowledge and provide a commonly agreed upon understanding of a domain. The advantages include the sharing and re-use of knowledge, and the better engineering of knowledge-based systems with respect to acquisition, verification and maintenance. In this paper, we propose a unifying framework (e.g. including configuration, outstanding traffic monitoring and analysis, planning and management, tutoring, etc.) for supporting intelligent DNS management using web interface and expert system technology to help inexperienced administrators in insuring the smooth operation of their DNS systems. To help extract knowledge, we propose an efficient DNS Ontology Construction Algorithm to fast conceptualize DNS domain knowledge through a hybrid method of brainstorming and use cases modeling. While some sub-systems are still under development, others have been prototyped and deployed for everyday use. As our experience with a first simple prototype has shown, the paradigm of using DNS ontology to build a unifying framework for intelligent DNS management works good and effective. It is supposed that all these might become an integral part of the DNS administration activities of an organization in the near future. (C) 2003 Elsevier Science Ltd. All rights reserved.