【作者】 钱志军；

【导师】 李长山；

【作者基本信息】 大庆石油学院 ， 计算机软件与理论， 2007， 硕士

【摘要】 OSPF是IETF(Internet Engineering Task Force)提出的一种基于链路状态的内部网关路由协议。OSPF通过传递、交换路由器的链路状态来得到整个网络的信息,从而维护一张网络有向拓扑图,利用最小生成树算法(SPF)得到路由表。OSPF路由器之间通过各种报文来实现维护一个分布式的链路状态数据库,其中存放链路状态信息。OSPF的报文中链路状态更新报文(Link State Update Packet, LSU)是携带路由信息的重要报文,它可将路由信息传递到目的路由器上,但是LSU在网络间扩散的过程极可能受到外来入侵者的篡改和恶意攻击。针对LSU携带的链路状态通告(Link State Advertisement, LSA)的最大年龄攻击、序列号攻击等都可使网络的稳定性和安全性受到影响。本文详细阐述了OSPF路由协议的运行原理、特点和OSPF安全性的意义。分析了OSPF路由协议网络类型、五种协议报文以及链路状态数据库的建立、同步、更新原理,并在此基础之上具体分析了OSPF路由协议的安全性,针对OSPF路由协议存在的诸多漏洞和可能受到的攻击提出了具体、实用的防范措施。然后在前人的研究基础之上,提出了一种基于LSU的数字签名OSPF保护机制,既减少了目前已经存在的LSA数字签名方案的开销又能很好的保护OSPF路由,并设计实现运行上述方案的路由器仿真系统,很好的验证了上述方案的正确性和可行性。最后,对本文提出的方案的安全性和效率进行了详尽的分析与验证。OSPF路由协议的安全性是网络安全中最重要的问题之一,对OSPF路由协议的安全性研究在可预见的很长一段时间里都将是网络安全研究的重要议题。对这方面的研究成果可大大增强网络的安全特性,具有很高的实用价值。更多还原

【Abstract】 OSPF is a routing protocol developed by IETF (Internet Engineering Task Force), it’s a Interior Gateway protocol based on the link state.OSPF gets the whole network’s information by exchange the link state information with all other routers. It keeps a map which describes the network’s topology, then use SPF algorithm to get the routing table. OSPF routers use five types of the packets to struct and maintain a link state database which is distributed structed on all routers in area. In these databases, routers save the same link state information. LSU (Link State Update Packet) is the most important packet in the OSPF’s packets, because it takes the route information from one router to any other routers. But, when the LSU transmit on the network, it may be attacked by any faulty routers or intruders. These attacks to LSA, like MaxAge attack, Serial Number attack, and so on, can affect the network’s stabilization and security.This article expatiate the OSPF routing protocol’s principle, the characteristic and the significance of OSPF’s security. Analyzed the principle of OSPF’s network type, protocol packets and LSDB’s structure, synchronize, update. Based on these, article analyzed OSPF routing protocol’s security. For those holes, give several schemes to fix these problems. In the third chapter of this article, we present an efficient solution, OSPF routing protocol based on the LSU digital signature protection, to resolve the link state routing update authentication problem. At the last chater of this paper, it discusses the issue of the efficient and spending for the OSPF routing protocol.The security of OSPF routing protocol is one of the most important problems in the internet security, the research on the OSPF routing protocol’s security will be the important issue on the network security. These results of this study can greatly enhance the network’s security.更多还原