Server unreachable Countermeasures _ surfing the Web

Everyone wants to surf on the Internet, can be downwind, all the way unimpeded, but the fact is not so! It is believed that most people may have encountered an error message that the Web server could not access, and that this error is related to many factors in addition to the hardware devices connected to the network. To eliminate such failures, you must first start from the bottom of the network communication, that is, you must first check, confirm the network's "physical layer" is faulty. When you confirm that the hardware device for the network connection is not faulty, the troubleshooting work that the Web server cannot access is only just beginning.

　　1, network connection, whether to enable

If the Windows 2000 Server system in the Web server does not enable the network connectivity feature of the local computer, any other client will be unable to remain connected to the Web server, which can easily be a symptom of a failure to access the Web server. Therefore, checking that the network connectivity feature is enabled on the server is one of the important steps in troubleshooting this failure.

When you check that the server's network connectivity feature is enabled, you can click the Start menu in the System desktop and click Settings/Network and dial-up connections in the Open Network Connections list interface to see if there is a "local Area Connection" icon (as shown in Figure 1);

Figure 1

If you see the icon, you must also double-click the icon with the mouse, in the next Open Local Connection Properties dialog box, see if the connection's status is "connected," and if it has a status of disabled, it indicates that the network connectivity feature in the server has not been enabled, and you must right-click "Local Area Connection" icon to perform the "enable" command from the pop-up right-click menu, which enables you to restart the network connectivity feature in the server.

Tip: If you are in the Network connection list interface, when you do not see the "Local Area Connection" icon, you may click the "Start"/"Run" command, in the Open System Run dialog box, enter the Service policy edit command "Services.msc", click "OK" button, open the System's Services List window , double-click the "Network Connections" project, and in the Service Properties Settings window that appears in Figure 2, check that the "Network Connections" service has been started, and if not, you can click the "Start" button and then from the "Startup type" Select Automatic in the Drop-down list, and then click the Apply, OK button so that you can see the Local Area Connection icon again in the Network Connections List window.

Figure 2

　　 2. IIS process, shutdown

As you know, when you manually troubleshoot a network virus, it is very likely that some useful process will be shut down accidentally; if you accidentally shut down the IIS process, the Web server on the server will not be able to start automatically, and any visitor who accesses the Web server will have a symptom that the server cannot access. To troubleshoot this symptom, you must start the IIS process in a timely manner. When you see if the IIS process is turned off, you can follow these steps:

Press the Ctrl+alt+del compound key on your keyboard to open the server System's Task Manager window, and then click the Process tab, and then in the corresponding tab page that opens, Check if there is a IIssrv.exe process name, if not, it means that the IIS process in the current server was accidentally shut down;

At this point you can click the Start/program/Administrative Tools/Internet Services Management command, in the Open IIS Management Console window, right-click the name of the destination Web server, and execute the start command from the pop-up right-click menu. The IIS process can be restarted successfully.

　　 3, routing failure, smart query

If you have confirmed that the Web server itself is normal by the above troubleshooting, but it is not possible to access the Web server through the client, then it is necessary to check that the routing information for the network connection is normal. As you know, any workstation that communicates through TCP/IP network protocol can automatically create a routing table information, can easily find the target server according to the routing table information workstation, and establish the access connection with the server; Considering the local client's routing table information, after each reboot of the system, will change automatically. Therefore, when you are unable to connect to the Web server, you can see if the local routing table information contains a "default gateway" to access to the Web server, and if not, you can add it to the local routing table information yourself to ensure that the workstation can access the Web server smoothly. To view local routing table information, you can follow these steps:

Click the start/Run command, in the Open System Run dialog box, enter the cmd string command, and then click OK to switch the system state to the MS-DOS environment;

Then, on the DOS command line, execute the "Route PRINT" command, and then you will see the routing table information from the local workstation in the interface shown in Figure 3. If you find that there is no routing information to the default gateway, you can add a record to the default gateway through the route add command, and then the workstation will automatically connect to the default gateway.

Figure 3

In addition, you can also use the Windows System built-in TRACERT command to find out whether the local computer to the Web server between each router and gateway is working properly, if one of the routers or gateways are in trouble, can cause Web server access error symptoms. When you look at the exact router or gateway error, you can first in the system's Start menu, execute the "run" command, in the Open System Run dialog box, enter the "cmd" string command, click the "OK" button, the System state switch to the MS-DOS environment ; then execute the tracert command on the DOS command line, it won't take long for you to see the results of the test, if the result information contains "<210.73.140.1> reports:destination net unreachable." , it means that a router with an IP address of "210.73.140.1" on the current network is unable to successfully connect, causing the local workstation to be unable to find the Web server.

4, Domain name resolution, is correct

If you use ping to ping the IP address of the Web server, but you cannot access the contents of the server through the URL, it indicates that there must be a problem with the name resolution in your workstation. To troubleshoot such a problem, you can follow these steps to step through:

The first thing to look at is whether the local Hosts file contains invalid entries for the corresponding Web server, and if so, it could cause the local workstation to fail to connect to the Web server because of a domain name resolution error. When you check the Hosts file information, you can first open the System's Explorer window and then go to the%systemroot%system32driversetc folder window (where%systemroot% represents the specific path where the Windows system resides). Locate the hosts text file;

Next, right-click the file, select the Open with option from the pop-up right-click menu, and select Notepad from the subordinate menu to open the hosts text file. Next, check if the text file contains address records about the Web server, if you find such a record exists, you may wish to check the IP address of the corresponding Web server URL is correct, if not correct, it must be modified correctly, and finally save the file. In this way, the hosts file in the future will be able to accurately resolve the Web server URL to the corresponding IP address, then the local workstation will be able to successfully access the server with the connection.

If your computer uses DNS as the domain name resolution method, you will also need to check that the local computer's DNS configuration is correct, or check the DNS servers on the local network for problems. When you check that the DNS configuration is correct, you can switch the system to MS-DOS mode first, then execute the "ipconfig/all" command on the DOS command line, and in the resulting page, see if the IP address of the local DNS server is set correctly, if not correct, You must open the Network Properties Settings window to reset the IP address of the DNS server.

　　 5, Web permissions, whether open

Sometimes we can connect to the Web server, but we can't open the content of the Web page in the server, what's going on? Encountered this phenomenon, the basic can determine the network connection between the client and server is normal, as for the phenomenon that can not open the Web page content, most of the Web server's permissions are not set properly. At this point, you can follow the steps below to check that the server's Web permissions are set correctly:

Right-click the My Computer icon in the System desktop. Then execute the Manage command from the pop-up right-click menu, expand the Services and applications/Internet Information Services Manager option in the Open Computer Management window, as shown in Figure 4;

Figure 4

  Then right-click the specified Web Server site. And execute the Properties command from the shortcut menu that opens, and in the next Web Site Properties Settings dialog box, click the Directory Security tab, and on the corresponding label page, anonymous access and authentication control　　Settings item Click the Edit button, and then in the

Pop-up Validation Method Settings dialog box, check to see if the Anonymous Access feature is enabled, and if the feature is not enabled correctly, it may affect the access to the Web server content;

In addition, return to the Web Server Site Properties Settings dialog box, click on the "Home directory" tab to see if the "Read files", "Directory Browsing" permissions in the corresponding tab page are open, and if not, you must select them, so that you may be able to access the Web server content smoothly.

6, Destination address, restricted

If the workstation that specifies the IP address can access the contents of the other Web server normally, you will not be able to access the content information of the specified server, you must check the server, Whether the IP address of the specified workstation is filtered, causing the workstation to have no rights to access the contents of the server. When you check that the server is filtering the IP address of the specified workstation, you can follow these steps:

Click Start/Programs/Administrative Tools/Internet Services Manager. In the following Open Internet Service Management Console window, right-click the name of the destination Web server site, and perform the Properties command from the pop-up shortcut menu;

in the next Web Server site Properties settings interface, click the Directory Security tab, and in the corresponding label page "IP address and Domain name restrictions" settings, click the Edit button, and then in the Edit Settings window that opens, see if the IP address of the specified workstation appears in the Access Denied list box, and if the address has been rejected, you must delete it in time, and then click OK button and refresh the IIS service so that the workstation with the specified IP address can successfully access the Web server.