The Study Of Security Based On IPSec VPN

The rapid development of Internet techniques and services provides conveniences in the exchange and sharing of information, but meanwhile it takes unprecedented hidden troubles to the security of network. The operability and normalization of IP(Internet Protocol) makes itself the standard of data exchange in Internet. But because of its inborn security vulnerabilities, it becomes the, target of kinds of network attacks.According to the five basic elements of information security (confidentiality, integrality, availability, controllability, non-denial), this dissertation discusses the security of IP. It presents solutions to several most common network attacks, especially brings forward a general method towards the DoS attack, which freezes illegal IP addresses based on exponent increasing frozen time.IPSec protocol provides efficient security assurance in the IP communications. IPSec VPN provides mature mechanism in data encryption, data-integrality validation, and non-denial of communicating entities. This dissertation makes a analysis and comparison between several main tunnel protocols, and particularly discusses the importance of IPsec in the aspect of security assurance.This dissertation mainly develops an idea of classified protection based on IPSec VPN, which has the following characters: make a classification to the data according to different security requirements, set access limits to different people; use history interrelated credit policy to a single firewall, use intensity classification and logic call policy between firewalls, this kind of classified firewall mechanism to provider flexible and efficient protections; use tag method to make firework and IPSec compatible. All of this complies with the PDRR model.