Solve problems with web server not accessible

Accessing the Web server is a "homework" that many LAN users often do. During frequent visits, many friends have accumulated some experience in Web server access. These experiences often help them quickly resolve some inaccessible small ones. malfunction. However, the Web server contributed by the following article can not access the fault phenomenon is quite special. If you do not analyze it carefully, it is easy to take a detour when solving the fault simply by experience. In order to help friends to access the Web server efficiently, the author will now This special network access troubleshooting process is restored, I hope everyone can receive inspiration from it!

Can Ping but can not access

A certain unit LAN is not large, a total of 18 ordinary computers In addition, a Web server with Windows Server 2003 system is installed. All common computers and Web servers are connected to a manageable core switch, and the LAN is shared by the broadband router. In normal times, the operating systems installed and installed in 18 ordinary computers are different. There are Windows XP systems installed, Windows Vista systems are installed, and two computers are still used. Windows 98 systems are still used, but these computers can be used normally. Access the web server in the LAN.

However, recently, when LAN users access the contents of the Web server site through Internet Explorer, an authentication dialog box appears on the system screen, asking the user to enter the appropriate username and password information; in fact, the Web server There is no authentication enabled at all. It usually allows any user on the LAN to log in and access the site content anonymously. So why is this happening now? What is even more strange is that the network administrator can not successfully pass the authentication of the Web server regardless of whether he enters the legitimate user account of the Web server or enters the super administrator account. What is the reason? When the network administrator attempts to use the Ping command to test the connectivity of the LAN target Web server, it is found that the Web server can be pinged normally. This also proves that the physical connection between the LAN common computer and the Web server is normal; In the case of a failure to access the Web server abnormally, it is likely that there is a problem with the Web server itself. //This article transferred from www.45it.com.cn computer software and hardware application network

Check Web site access permissions

At first, the network administrator thought it was the Web server itself set improperly, resulting in the LAN The user cannot access it normally. Considering that the web server suddenly requires authentication, the network administrator judges that the access rights of the web server are accidentally modified, so immediately enter the Windows Server 2003 server system, click "Start" /"Settings" /"Control Panel" Double-click the "Administrative Tools" icon in the Control Panel, then double-click the IIS Control icon, open the IIS console window of the corresponding system, find the site name corresponding to the target Web server, and then right-click the target site name. Execute the "Properties" command in the right-click menu to open the property setting window of the target site; click the "Directory Security" tab in the settings window, and click "Edit" in the "Authentication and Access Control" tab of the corresponding option settings page. " button, open the settings dialog shown in Figure 1, where the network administrator whether to select or uncheck "anonymous access", "integrated Windows authentication" and other options, the Web server still has to authenticate, which shows that The fault phenomenon is independent of the access settings of the target web server.

Checking Server Connection Limits

Since a valid user account or even a super administrator account is not properly logged into the web server, the network administrator is beginning to suspect that the Windows Server 2003 server system may be against the user. At the same time, the number of connections is limited because once the number of web home directory user connections to the web server is limited, the user who quits the login does not access the site content in the web server anyway. With this in mind, the network administrator first opens the resource manager window of the server system, finds the site home directory of the web server, right-clicks the directory icon, and executes the "properties" command in the shortcut menu to open the target site home directory. The property setting window; click the "Share" tab in the settings window, in the corresponding option settings page, the network administrator really found that the Windows Server 2003 server system limits the number of user accesses in the directory to 5, so try The parameter is changed to 20, and the setting operation is saved. When the web server is accessed again, the same failure phenomenon still occurs.

Later, when the network administrator queried the information about the user connection restrictions, it was found that if the authorization mode of the Windows Server 2003 server system was set incorrectly, the number of user connections would be limited. After searching for such a result, the network administrator was excited about it. It seems that the failure phenomenon that the Web server cannot access can be solved immediately; he immediately opens the "Start" menu of the Windows Server 2003 server system, and then clicks "Settings". " /"Control Panel" command, and double-click on the "Authorization" option, in the subsequent interface, the network administrator found that the server system selected the "per server" option by default, while seeing the number of user connections is displayed as " 5", it is obvious that the parameters here are not set correctly. The network administrator immediately selected the "per device or user" option here (as shown in Figure 2), then selected the "I agree" option in the per device or per customer authorization dialog, and finally restarted the server system; I thought that such an effort would certainly be rewarding, but when I re-accessed the LAN web server from a normal computer, there was an annoying authentication dialog on the system screen.

Unexpectedly Finding the Cause of the Fault

Just as the network administrator has no clue, a LAN user suddenly ran to ask the network administrator for help, saying that their department needed to work, recently I bought a network printer, connected the network printer to the core switch of the unit, and set the relevant network printing parameters. All users in their department can use the network printer to print materials normally, but today, he My computer can't use a network printer, and others can print online. Upon hearing the user's request for assistance, the network administrator immediately went to the network printer site, logged into the printer background management interface, and occasionally opened the log page of the network printer, found the IP address of the network printer and the IP address of a computer in the LAN. When a conflict occurs, and then carefully check the conflicting IP address, it is actually the IP address used by the Web server. No wonder the Web server cannot access it properly. The original IP address of the network printer has an unexpected conflict with the IP address it uses.

Originally, for the convenience of management and maintenance, a web service is also running on the network printer. Users can set various Internet access parameters of the network printer through the web-based background management interface, but the network printer The Weh server with the support does not support anonymous access by default. When the IP address set by the user for the network printer conflicts with the web server address, when the LAN user enters the IP address of the web server in the address bar of the IE browser window, the user actually accesses the background login interface of the network printer, which is also Why the authentication dialog appears on the system screen when accessing the web server. At this time, when the Ping command is used to test the connectivity of the Web server, the network printer is tested, so that the network printer can be pinged, but a legal user account needs to be input to access.

After clearing the cause of the failure, the network administrator immediately modified the IP address of the network printer to ensure that the IP address of the Web server did not conflict with the IP address of other computers. As a result, when accessing the Web server again, it was true. The content of the page can be opened very quickly, and the failure phenomenon that the web server can ping but cannot be accessed is successfully solved.

The final summary

This kind of network failure is not very complicated to solve, and it is sure to find the final cause of the failure. However, this fault reminds us from every angle that every network administrator can not blindly apply the experience to solve network failures. Instead, familiarize yourself with the latest changes in the network environment before troubleshooting, and be familiar with the various network devices in the working environment. Functional characteristics, only know the latest changes in the network and the various characteristics of the network equipment, we will subconsciously think and associate in the event of network failure, the only way to quickly find the specific cause of the failure, and in a timely manner Take measures to quickly resolve network failures.