Avaya 555-245-600 사용자 설명서

다운로드
페이지 378
VPN
Issue 6 January 2008
301
 
Firewall technologies
To reduce security risks, appropriate network access policies should be defined as part of 
business strategy. Firewalls can be used to enforce such policies. A firewall is a network 
interconnection element that polices traffic the flows between internal (protected) networks and 
external (public) networks such as the Internet. Firewalls can also be used to “segment” internal 
networks.
The application of firewall technologies only represents a portion of an overall security strategy. 
Firewall solutions do not guarantee 100% security by themselves. These technologies must be 
complemented with other security measures, such as user authentication and encryption, to 
achieve a complete solution.
The three technologies that are most commonly used in firewall products are packet filtering, 
proxy servers, and hybrid. These technologies operate at different levels of detail, and thus they 
provide varying degrees of network access protection. That means that these technologies are 
not mutually exclusive. A firewall product may implement several of these technologies 
simultaneously.
Network management and outsourcing models
While enterprises acknowledge the critical role that the Internet and IP VPNs can play in their 
strategic eBusiness initiatives, they face a range of choices for implementing their VPNs. The 
options range from enterprise-based or “do-it-yourself” VPNs that are fully built, owned, and 
operated by the enterprise, to VPNs that are fully outsourced to a carrier or other partner. In the 
near term, it is generally believed that enterprise-operated and managed VPN services will 
hover around a 50/50 split, including hybrid approaches.
Increasingly, enterprises are assessing their VPN implementation options across a spectrum of 
enterprise-based, carrier-based/outsourced, or hybrid models. Each approach offers a unique 
business advantage.
Enterprise based. This option operates over a public network facility (most commonly the 
Internet) using equipment that is owned and operated by the enterprise. Its greatest 
benefit to the enterprise is the degree of flexibility and control it offers over VPN 
deployment, administration, and adaptability or change.
Fully outsourced. This managed service could be implemented by a collection of 
partners, including an ISP and a security integration partner. Its advantages include quick 
deployment, easy global scalability, and freedom from overhead network management.
Shared management. With this hybrid approach, a partner can take responsibility for 
major elements of infrastructure deployment and management, but the enterprise retains 
control over key aspects of policy definition and security management.