Troubleshoot Failures caused by failures in the Intranet

Push through multiple layers to prevent Intranet access failures

In order to apply for a permanent examination site for intermediate and middle-level computers, the organization established a standard LAN machine room for students to conduct intermediate and middle-level training and examinations at no cost of RMB 100,000 last year; the local area network mainly includes 36 P4-level founder brand computers, two cascade Cisco-branded 10 M/M Adaptive switches, and an HP Server with two NICs installed, the server is installed with the Windows 2000 server operating system, while other workstations are installed with the Windows 98 operating system required for the preliminary intermediate computer examination.

Recently, the Organization has to hold a training course on Internet. In order to achieve the goal of online training, the Organization's leadership asked the author to find a way to make a small transformation to the LAN, this allows each workstation to smoothly and conveniently access Internet content. After receiving the task, I first checked the current connection status of the LAN and found that all workstations are connected to the switch. The Windows 2000 Server directly connected to the Internet through a network card, another Nic is connected to the vswitch. In view of this, the first thing I think of in my mind is to use the built-in Internet Connection Sharing function of Windows 2000 to achieve the requirement that the Intranet can also access the internet. The general idea of this method is: one network card of the server is directly connected to the LAN Intranet through a switch, and the other network card is directly connected to the Internet, and then the connection sharing function is enabled for the network card connected to the Internet, in this way, all Intranet workstations can access the Internet.

Based on this idea, the author and another colleague quickly took action, bought a network cable and a crystal head, prepared relevant networking tools, and prepared a network cable for connecting to the Internet; connect one end of the crystal head to a NIC of the server, and the other end is connected to the RJ-45 port of the broadband optical fiber conversion device. Next, open the network attribute settings window of the server, go to the TCP/IP parameter settings page, and assign an independent public IP address to the network adapter connected to the Internet, at the same time, the gateway IP address and DNS server address are configured. below, the Internet Connection Sharing function of the Internet Nic is enabled manually. Once this function is enabled properly, the IP address of another Nic connected to the Intranet in the server is automatically changed to "192.168.0.1", and the network mask address is automatically set to "255.255.255.0 ", at this time, you can manually set the DNS parameters for connecting to the Intranet Nic, and then click "OK" to complete all the parameter setting tasks on the server. Next, the author and colleagues split their heads to open the TCP/IP parameter settings window for each workstation, and set their IP addresses to 192.168.0.2, 192.168.0.3 ......, In addition, the network mask address is set to 255.255.255.0, the gateway address is set to 192.168.0.1, And the IP address of the DNS server is set to the same as the DNS address of the server.

After completing all the setting tasks, you can find a workstation at will, open the system running dialog box, and run the "Ping 192.168.0.1" command in it, the execution results show that the internal connection and network settings of the LAN are all normal. I thought that any workstation would be able to access the Internet. At this point, another colleague needs to download a compression software on the Internet. He can open the IE browser, enter the URL of the huajun Software Park, and find that the home page of the website cannot be opened; later, the colleague entered another website, but still could not access the internet. From the status bar of the IE browser window, I found that the domain name address of the target website has been correctly resolved to an IP address, but the website content cannot be opened.

Will it be that the server has not been connected to the Internet? However, when I open the IE browser window on the server and enter a URL at will, the webpage content will soon be displayed. Obviously, the server can access the Internet normally; is there a problem with the workstation selected by my colleagues? So I opened the system operation dialog box in the workstation just now, and pinged the gateway address and some internet site addresses. The test results all showed that the network connection was normal. Since the server side is normal, the network connection settings are also normal, will it be a client?Program-- Is ie damaged? At this point, I had to think about what to do. Open the running dialog box of the system workstation and execute the string command "SFC/scannow" in it ", then, the system found that several items of IE were damaged. I fixed them one by one, restarted the computer system, and opened the IE browser again for testing, the Intranet is still inaccessible. I am still unwilling to do so. I also clicked the "Tools"/"Internet Options" command in the menu bar of the IE browser to carefully check the browser's Internet Settings, after checking, I found that the "Automatic Detection Settings" option in "LAN Settings" was not selected. However, I reselect this option and exit the Internet option settings window, when I tested the Internet, there was still no progress. I had to open another workstation to test the Internet, but the result was still unable to access the Internet. what's even more surprising is that no matter which workstation I open, the final test results were the same, that is, the webpage content cannot be opened.

Oh, no achievements have been made since I was busy? I cannot help but sigh! In addition, I have moved my eyes to the server. After all, if every workstation cannot access the Internet, I can basically conclude that the failure of Intranet access is irrelevant to the client. Open the server's network neighbor window, I found that the figure of other workstations can be seen here, and no matter which website the server accesses, IE browser can quickly display the website content, these phenomena indicate that the server should have no problems in network parameter settings. Then I wonder if the virus on the server is "messing up? No matter whether the server is infected with viruses or not, find the latest version of Rising antivirus software to thoroughly scan and kill the server system. After a long wait for virus detection and removal, several new viruses have been detected on the server, but unfortunately these viruses have almost nothing to do with the failure to access the Internet over the Intranet, because after these viruses are cleared, the Intranet is the one that cannot access the Internet.

Is there really no way to access the Internet through the Intranet? In desperation, I calmed down and reviewed all the system settings that may affect the internet access. I suddenly thought that the server was set as a LAN router, will the system's "Routing and Remote Access" function affect Intranet access? As a result, I opened the System Service List window, temporarily disabled the "Routing and Remote Access" service, and then restarted the server system. I thought this fault could be solved, but the actual online test once again gave me a relentless blow. The intranet is still "indifferent "!

When I was about to give up, a firewall window pops up on the screen, prompting me that my application needs to access the external network. Such a prompt is undoubtedly a result of the snow, because I have been so busy that I have ignored the role of the software. I believe that the failure of the Intranet to access the Internet is definitely caused by the firewall, So I immediately shut down the enabled firewall, and then opened the IE browser for testing, but the Intranet still cannot open the webpage content. Despite this, I am still not discouraged. In order to minimize the impact of firewalls or other software on servers, I intend to completely uninstall some temporarily unavailable software and firewalls, in this way, the server is in a relatively "clean" Environment for Intranet Internet access testing. When you open the control panel window on the server, double-click the "Add/delete programs" icon, and you want to uninstall the software in the displayed Application List window, I found that both Ms-proxy and WinGate Proxy servers are installed on the server. Oh, the server was used as a proxy server for the lan. Other workstations shared the Internet through ms-proxy or Wingate agent software! Does ms-proxy or Wingate software run quietly in the background, resulting in a conflict between the Internet Connection Sharing Method and the proxy server sharing method, the author subconsciously believes that this may be the crux of the problem that the Intranet cannot access the Internet.

To verify my own ideas, I removed all the proxy servers MS-proxy and Wingate from the system in the "Add/delete programs" Application List window, after restarting the server system, I carefully opened the IE window of a workstation, entered the website address of huajun Software Park again, and clicked the Enter key, ie started searching for the website address again. Fortunately, this time I was not disappointed with IE, and soon I opened the homepage of huajun Software Park. At this point, I was not at ease, and randomly entered the URL addresses of other websites for testing. The test results finally relieved me that I could access the Internet content freely on the Intranet. At this point, it is not difficult to find that the Intranet in this example cannot access the Internet, but it is actually caused by a conflict between software related to Internet sharing.