毕业论文-基于GRE-over-IPsec-VPN设计与仿真

摘 要

人类社会已经进入21世纪，计算机信息网络已深入到世界的各个角落，地域、国家、政府、企业甚至家庭。计算机网络的飞速发展给人来带来了诸多便利，而然其潜在的网络信息安全威胁也弥漫在各个领域。

本课题设计与论述的是关于网络安全中常用的一种技术——虚拟专用网（VPN）技术。该技术的主要作用：将不在同一区域的内网之间，通过在互联网中建立一种安全隧道，使得内网数据流安全地穿越互联网，而不被外网用户获悉，从而保证内网之间的数据通信安全地穿越互联网。

本课题所探讨的VPN技术则是建立在GRE over IPSec技术之上，并通过合肥百大集团的网络拓扑对其进行设计与仿真。

GRE over IPSec VPN技术是通过GRE与IPSec相结合，而形成的一种安全性更好VPN技术，其主要借用IPSec的安全加密和GRE支持多播的优点，从而使得VPN网络更加安全。该项技术的主要工作原理：将一个完整的组播、广播数据包或非IP数据包封装在一个单播数据包（IPSEC）里，以处理如OSPF的组播或 RIP的广播数据流，以完成在IPSec隧道里通信实体之间的动态路由学习。

关键字：网络安全，VPN，IPSec，GRE，动态路由协议（具体是OSPF协议）

I

Abstract

The human society has entered the 21st century, and the computer information network has penetrated every corner of the world, regional, state, government, businesses and even families. The rapid development of computer networks has brought much convenience to people, and then the potential security threat network information filled in the various fields.

Design and discussion of the topic is about a kind commonly used in network security technologies - virtual private network (VPN) technology. The main function of the technology: the network is not within the same region between the Internet by establishing a secure tunnel so that data flows within the network through the Internet safely without the user was informed by external network, thus ensuring the network between secure data communications through the Internet.

The topics are discussed in VPN technology is built on top of GRE over IPSec technology, and through Hefei Baida Group to design their network topology and simulation.

GRE over IPSec VPN technology is through the combination of GRE and IPSec, and the formation of a better VPN security technology, its main borrowing GRE IPSec encryption and security advantages of multicast support, which makes the network more secure VPN. The main working principle of the technology: a complete multicast, broadcast packets or IP packets are encapsulated in a unicast packet (IPSEC) in order to deal with, such as OSPF or RIP broadcast multicast data streams to complete the communication entities in the IPSec tunnel between the dynamic routing study.

Keywords: Network Security, VPN, IPSec, GRE, Dynamic Routing Rrotocols (specifically,

the OSPF protocol)

II

目 录

摘 要 .......................................................................................................................................... I Abstract .......................................................................................................................................... II 第一章 网络安全与VPN简介 ..................................................................................................... 1

1.1网络安全简介 .................................................................................................................... 1 1.2 VPN技术简介 ................................................................................................................... 2 第二章 GRE over IPSec VPN相关技术描述............................................................................... 5

2.1 GRE隧道协议 ................................................................................................................... 5 2.2 IPSec概述 .......................................................................................................................... 6 2.3 AH和ESP ......................................................................................................................... 9 2.4 IKE协议 .......................................................................................................................... 12 第三章 系统VPN分析与概要设计 ........................................................................................... 17

3.1系统VPN需求分析 ........................................................................................................ 17 3.2系统VPN规划与概要设计 ............................................................................................ 18 3.3系统VPN规划与概要设计 ............................................................................................ 20 第四章 GRE over IPSec VPN相关技术分析............................................................................. 22

4.1 GRE基本配置与分析 ..................................................................................................... 22

4.1.1 配置网络环境 ....................................................................................................... 22 4.1.2 配置GRE VPN ..................................................................................................... 23 4.2 IPSec基本配置与分析 .................................................................................................... 24

4.2.1 IPSec VPN基本配置步骤 ..................................................................................... 24 4.2.2 IPSec VPN安利配置与分析 ................................................................................. 26 4.3 IPSec over GRE VPN和GRE over IPSec VPN基本配置与分析 ................................ 36

4.3.1 IPSec over GRE VPN配置与分析........................................................................ 36 4.3.2 GRE over IPSec VPN配置与分析........................................................................ 42 4.3.3 GRE over IPSec VPN与IPSec over GRE VPN的区别 ...................................... 46

第五章 基于GRE over IPsec VPN设计与仿真的实现 ............................................................ 47

5.1 GRE over IPsec VPN配置与实现 .................................................................................. 47 5.2 查看本系统GRE over IPsec VPN配置文件 ................................................................ 54 5.3 网络系统调试与分析 ..................................................................................................... 59 结 论 ....................................................................................................................................... 66

一、技术要点和难点 ............................................................................................................ 66

（一）技术要点 ............................................................................................................. 66 （二）技术难点 ............................................................................................................. 69 二、设计中遇到的问题 ........................................................................................................ 71

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三、毕业设计总结 ................................................................................................................ 73

（一）个人体会 ............................................................................................................. 73 （二）专业和技术总结 ................................................................................................. 74 （三）方案总结 ............................................................................................................. 75

参考文献 ....................................................................................................................................... 76 致 谢 ....................................................................................................................................... 78 附 录 ....................................................................................................................................... 79

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