IPSec及其在动态IP隧道协议L2TP中的应用

L2TP是虚拟专用网中常用的隧道协议,在隧道建立过程中,Responder可以动态选择IP地址。本文分析了L2TP中存在的安全性隐患,提出并描述了一种允许L2TP向IPSec过滤规则库中动态添加规则,实现IPSecESP为L2TP提供安全保护的方法。     

基于L2TP/IPSEC的安全隧道技术方案

分析L2TP协议实现VPN时存在的安全问题,提出一种将L2TP协议和IPSec协议相结合,利用．IPSec为L2TP协议提供保护的安全隧道技术方案．     

基于L2TP/IPSec的VPN技术在校园网中的研究和应用

分析了L2TP协议的安全隐患和IPSec协议的强安全性,指出在L2TP隧道中,利用IPSec协议封装负载数据,可构建安全性能更强的虚拟专用网络,并根据基于L2TP/IPSec协议的VPN系统的特点,从校园网应用角度探讨了VPN技术在校园网校区之间、服务器管理、远程接入等方面的应用,分析了目前存在的问题及解决方案展望.     

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.     

浅析虚拟专用网络中的隧道技术与安全技术

本文分析了点对点隧道协议(PPTP)、第2层隧道协议(L2TP)、安全IP(IPSec)隧道协议、SOCKS v5协议,并简要介绍了VPN的加密解密、密钥管理、认证等安全技术。     

电子商务中的虚拟专用网技术

虚拟专用网(VPN)技术的出现，为电子商务的实现提供了快速安全但又相对便宜的手段。本文介绍了实现VPN的隧道技术及相关的协议，如：PPTP协议、L2TP协议、IPSec协议等，以及VPN的类型和安全技术。     

谈虚拟专用网组建

本文介绍了在WmdowsXP平台上用IPSec协议实现VPN（Vtrtual Private Network）技术。介绍了VPN的研究意义和目的及IP—Sec实现VPN的关键技术,包括隧道的基本概念、隧道技术及其应用、PPTP协议、L2TP协议、IPSec协议、安全、等技术,涵盖了从路由环境到VPN服务器和客户端的配置、以及VPN连接的实现方式和在企业中的应用。     

虚拟专用网VPN关键技术的探讨

讨论了在实现虚拟专用网VPN中起决定作用的关键技术，如L2F、PPTP、L2TP和IPSec等各种隧道封装技术，并对其安全性进行了分析．可以看出，利用IPSec技术具有对原始数据的高安全保障和PPTP或L2TP的易管理维护的特点，可以构建出一条较完善的VPN通道．     

IPSec在应用中与双向NAT的兼容方案

在广泛应用的基于IPSec的VPN系统中,为解决NAT出现给网络安全带来的复杂性,针对IPSec协议与NAT协议所存在的矛盾,并从VPN系统的角度提出了协作方式基于隧道接力的IPSec解决方案,从而解决了IPSec隧道穿透双向NAT的问题,最后进行了设计实现.     

VPN认证协议

VPN是通过隧道技术在公共网络上搭建企业自己的专用网络，同时对VPN的多种实现方案如L2TP协议、PPTP协议、L2F协议等进行了研究和分析，通过建立一个安全的VPN，以保证网络数据传输安全。     

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.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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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