Network breaking state of LAN is "master" by DNS server

In the stock market increasingly hot, the whole people crazy stock market today, many units employees in the work period is not the first task, but the Internet to inquire stock information, online analysis of the stock market, as the unit boss certainly do not want their employees to work during the job unrelated things, Is there any way we can make the Internet connection of workstations in the local area network control in the boss's own hands? Someone might say, "It's not easy to do!" Just unplug the workstation to the network cable in the switch, or temporarily disable the NIC device from the workstation, and solve the problem. However, these control methods are relatively "barbaric", not only easy to cause "popular anger", but also may affect the local area network of those important workstations work, and the control efficiency of these methods is very low.

In fact, most of the workstations are in the LAN server through the Routing and forwarding function to achieve the sharing of Internet, we can skillfully use the DNS forwarding function in the server, to very simple and easy to control the LAN Workstation network connectivity State, to ensure that the LAN access state by the DNS server "as the main ”！ Below, this article takes the Windows 2000 system server as the operation Blueprint, to detail how to use the DNS service forwarding function to effectively control the network running state of the workstation in the LAN.

Network On-off Control Environment

Suppose the unit LAN has 20 common workstations, a server with Windows 2000 system installed, they are connected to a 24-port switch at the same time, the IP address of each normal workstation in the LAN is dynamically allocated by the server's DHCP service. And they are all through the Windows 2000 Server routing forwarding function to achieve shared Internet access, and Windows 2000 servers through the ADSL device directly dial-up Internet. In order to be able to access content on the Internet network, each workstation takes the DNS server in the LAN as the domain name resolution server; Now we want every workstation in the local area network to be unable to perform a normal domain name resolution through the DNS server. That way, at work, every workstation will not be able to surf the Internet online to view information or watch the stock market.

Network break-through control preparation

To ensure that workstations in the LAN can use DNS servers in the intranet, we first install and set up the DNS service on the Windows 2000 Server. By default, the Windows 2000 Server does not have the DNS service installed, so we can click the Start/Settings/Control Panel command in the server System desktop, then double-click the Add or Remove Programs option in the interface that pops up, and then click Add/ Remove the Windows Components tab, open the Windows Component Add Wizard dialog box (shown in Figure 1), select the Network Services option in the component list by using the mouse, and then click the "Details" button below the option to go to the Network Services list interface and select "DNS Service" from the list interface. Then click the Next button and follow the wizard prompts to complete the rest of the installation operation, so that the DNS service components on the Windows 2000 Server are installed successfully.

Figure 1