Avoid Public DNS Information for VPN Servers and Routers

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Chapter 11. A VPN Scenario

If you havent gotten enough of the virtual private network yet, this chapter will cover a real, live, up and running VPN. Weve covered the theory and some general cost-to-benefit analysis, and now we move on to some actual products working in a production environment. Though we have used specific products here like Ascend and Cisco, you may well find that other solutions better fit your enterprise. In other words, this chapter isnt VPN law, just an example.

11.1 The Topology

Well call the company in this case study Immediate PC. It manufactures and sells computer parts and peripherals. About a year ago, Immediate PC made the commitment to standardize its network communications between its various sites over the Internet. Naturally, their main concerns were security, cost, and reliability. Communication needs at Immediate PC are like those at most companies. Sales agents in the field must communicate with manufacturing managers at the factories to order and ensure production of needed stock. The retail store arm of the company also communicates with shipping, manufacturing, and several other departments on a daily basis. Various factories and other divisions across the country must send and obtain data to keep their operations flowing. Several different platforms are used at various levels of the organization. The main corporate network is comprised of Windows NT servers and Windows NT or Windows 95 workstations. Additionally, there are several Unix servers of various flavors. Remote access users employ a variety of operating systems, and a few departments within the main corporate networks use Macintosh systems. Without the Internet, the flow of data and the cost associated with private lines and dial-up access were crippling operations and eating into profits. Having decided to use advanced technology to remedy the situation, Immediate PC migrated gradually from private lines and remote access to a controlled use of the Internet. Research, training, and various levels of approval preceded the move to virtual private networks. After this move, the company reduced the cost of network communication and resolved several communications problems. What emerged was the virtual private network detailed in the network diagram at the end of this chapter. The chosen architecture links a central corporate office with various remote offices, large and small, in addition to a gaggle of remote access users. The following sections detail what was needed in connections to the Internet, equipment, software, and virtual private network solutions.

11.2 Central Office

The central office is the natural source of information about products and operations. Security is critical. Besides the VPN, several other Internet services are centralized here, including the