GRE over IPsec VPN结合NAT的构建方案研究与实现

IPSec和GRE均为构建虚拟专用网所采用的技术,其自身都有其局限性,IPSec不支持广播、组播和非IP数据流,而GRE不支持数据加密.分析了IPSec和GRE各自的优势,结合IPSec的安全性和GRE对广播、组播和非IP数据流支持的特点,提出了GRE over IPSec VPN结合NAT的构建方案,实现了两个局域网之间单播或组播数据的保密通讯,通过运行EIGRP协议交互内网路由信息,进而使用NAT技术实现局域网内部用户脱离VPN访问Internet.依据提出的构建方案,绘制了组网拓扑图,并基于GNS3进行了仿真实验,验证了方案的安全性和可实施性.该方案既满足了不同局域网之间安全通信的需要,也满足了局域网内部用户访问Internet的需求.     

基于安全GRE隧道的Site-to-Site VPN构建方案研究与实现

为了实现经由Internet连接的两个私有网络之间能够利用隧道技术以私有IP地址的方式相互访问其内部资源,并且可以在隧道中传递动态路由协议信息,在基于Cisco路由器的配置过程中,通过利用GRE与IPSec两种技术共同构建Site—to—Site VPN,即首先使用GRE协议对用户数据和路由协议报文进行隧道封装。然后通过IPSec提供的数据机密性、数据完整性验证以及数据源认证功能保护在GRE隧道中传送的敏感数据,以实现GRE隧道的安全传输。通过结合GRE可支持承载IP组播流量与IPSec提供的安全特性创建Site-to-Site VPN,既解决动态路由协议在IPSec VPN隧道内正常通告的问题,又可以保护敏感数据穿越不安全通道的安全性。     

基于IPSec的VPN网络安全的实现

基于加密学基础的IPSec协议是解决公用网上IP数据传输安全性的一个有效手段。文章通过研究和分析IPSec协议,提出了Linux操作系统下IPSec安全网关和VPN(虚拟局域网)系统的构建方案,实现了一种根据信息安全技术的研究基础以及工程实际需求提出的基于IPSec的VPN的网络信息安全体系。     

基于外网构建安全可靠的内网

通过对IPSec安全协议的分析，研究了基于IPSec虚拟专用网络VPN的安全性及如何利用公网构建安全可靠的内网，使校园网利用不可靠的公用互联网作为网络传输媒介，实现了专用网络的安全性，提高了网络的安全等级，具有一定的实用性。     

在局域网中IPSec与NAT冲突的解决方法

IPSec主要是通过对整个IP报文进行加密和认证,防止外部对IP头信息的访问来提供安全服务,而NAT要访问或者修改IP报文的头信息。局域网内用户如何让IPSec、NAT协调工作,本文提出了一种解决方案,该方案主要是在数据报文应用完IPSec协议之后增加一个外部头,这个外部头可以方便NAT处理又不与IPSec产生冲突,实现了两者的协调工作。     

基于GRE over IPSec技术实现芜湖市委党校VPN专网建设

随着VPN技术应用的日益广泛,IPSec已经成为实现VPN的主要技术。本文根据党校现在的网络建设需要,通过对IPSec和GRE的分析,把这IPSec和GRE配合起来使用以实现GRE over IPSec技术在芜湖市委党校VPN专网中的建设。     

集成L2TP和IPSec技术构建安全的远程接入虚拟专用网

目前远程接入VPN主要基于L2TP协议实现,但是L2TP隧道传输协议本身没有为通信提供任何形式的安全保护,因此这种结构的VPN存在着安全隐患.为了解决这个问题,在研究远程接入VPN特点和功能基础上,利用IPSec协议为L2TP协议提供安全保护,提出了集成L2TP和IPSec构建安全的远程接入VPN方案.     

基于IPSec的VPN网关研究

随着网络技术的飞速发展,VPN作为一种新型的远程网络访问技术,在近两年内受到企业用户的广泛关注.而作为VPN技术中最为重要的隧道技术,IPSee协议目前还是被公认为最安全,应用最为广泛的隧道技术.探讨了基于IPSec的VPN网关实现技术,并给出了一个实现方案.     

基于PPTP/IPSec的VPN研究及应用

利用公共网络平台创建虚拟专用网络,是当前解决外网用户对内部网络访问问题的最有效方法。提出了一种内部网络实现VPN的方法。该方法以Windows Server 2003路由协议、远程访问技术为基础,并结合了IPSec加密技术、PPTP隧道协议构建了IPSec VPN虚拟网络。实验证明该方法安全性较高、运行稳定且易于实现。     

IPv6网络安全体系结构分析与应用研究

分析了下一代互联网通信协议:IPv6的网络安全体系结构IPSec,其中包括安全联盟(SA)、认证头(AH)、封装安全载荷(ESP)和Internet密钥交换(IKE);分析了实施IPSec的策略;最后对利用IPSec构建虚拟专用网(VPN)和IPSec在无线局域网(WLAN)的应用进行了研究。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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