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Article ID: 832161 - Last Review: July 16, 2007 - Revision: 6.7

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SUMMARY

This article describes a problem where you experience long delays when you log on to the domain and when you open network shares. There are a variety of possible causes. These causes include problems with the WebClient service, problems with proxy settings, and problems with the server configuration.

One easy test that you can use is to turn off the client computer's WebClient service or the server's service that is listening to Transmission Control Protocol (TCP) port 80. If either of these workarounds resolves the problem, there are ways that you can re-enable these services and reduce the delay. Update to the latest service pack for Windows XP, bypass the proxy server for local servers, change the order of network providers so WebClient is the last provider, install any updates to the WebClient service, and then make adjustments to your Internet Explorer configuration.

SYMPTOMS

When you use a computer that has an operating systems installed that is listed in the "Applies to" section, you may experience one or more of the following symptoms:
  • After you type your password at the logon screen, the computer may appear to stop responding (hang). This behavior occurs from the time when Group Policy is processed until the time that a blue screen appears, just before the desktop icons appear. This can last several minutes.
  • During the logon process, you see an "Applying Computer Settings" message for several minutes. However, you can log on the same computer quickly when the network connection is unplugged.
  • There is a long delay when you try to open a network share.
  • When you try to open a file that resides on a Distributed File System (DFS) share, it may take from 90 seconds to 15 minutes to open. However, you may be able to quickly open the same file by using the direct path of the file.
  • When you use Microsoft Internet Explorer 6 to access shares on a Microsoft Windows NT 4.0-based server or on a Microsoft Windows 2000-based server, access to the shares may appear to stop responding (hang).

    Note You may gain access to the requested shares if you wait a long time, perhaps10 minutes or more.

CAUSE

In each of these symptoms, the computer must open a network share. The request to open the network share uses the Uniform Naming Convention (UNC) path \\Servername\Sharename\Directory\Filename.ext. The UNC location is first passed to the WebClient service. The WebClient service may try to connect to http://Servername/Sharename. The WebClient service may try to use the Internet extensions for Windows to contact Web Distributed Authoring and Versioning (WebDAV)-enabled servers through the proxy server. The proxy server tries on port 80 to contact the destination server. One or more of the following causes delays in access to the share:
  • The WebClient waits for a response from the proxy server. The response may never be sent. If the response is never sent, there is a delay until the WebClient times out. The default for this delay is 10 minutes.
  • If the destination server does not support HTTP on TCP port 80, or if the destination server is offline, the proxy server may not send the expected HTTP error code back to the WebClient.
  • If there is a dead external DFS server reference on the proxy where the request is passed, the delay can be because of the timeout for the external DFS connection failure.
  • The Network Provider Order lists Web Client Network before it lists Microsoft Windows Network.
  • The domain controller that is used for authentication runs a service that listens on TCP port 80. For example, the domain controller is also an Exchange server with Outlook Web Access (OWA).
  • Internet Explorer's proxy server settings are not configured as Bypass proxy for local addresses. Also, local intranet Fully Qualified Domain Names are not entered in the exclusion list.
  • The PATH statement variable contains a reference to a DFS link, such as the following:
    PATH=\\corp.domain.com\dfsroot\DFSLink;C:\WINDOWS\system32;

RESOLUTION

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756  (http://support.microsoft.com/kb/322756/ ) How to back up and restore the registry in Windows


As a quick test, try the steps in the "Workaround" section first. If the "Workaround" section resolves the issue, the issue was caused by the WebClient service. If the "Workaround" section does not resolve the issue, the issue is outside the scope of this article.

If one or more of your applications requires the WebClient service, and the "Workaround" section applies to the issue, use each method in the order presented until the behavior is resolved.

Method 1: Install the latest Windows XP service pack

To verify that you have Windows XP SP1 installed, follow these steps:
  1. Right-click My Computer, and then click Properties.
  2. On the General tab, under System, locate the service pack version.
For more information about how to obtain the latest service pack, click the following article number to view the article in the Microsoft Knowledge Base:
322389   (http://support.microsoft.com/kb/322389/ ) How to obtain the latest Windows XP service pack

Method 2: Configure Internet Explorer to bypass the proxy server

To configure Internet Explorer to bypass the proxy server for local addresses, follow these steps:
  1. Start Internet Explorer.
  2. Click Tools, and then click Internet Options.
  3. Click the Connections tab, and then click LAN Settings.
  4. If the Use a proxy server check box is not selected, go to the next method.
    If the Use a proxy server check box is selected, click to select the Bypass proxy server for local addresses check box.
  5. Click Advanced.
  6. In the Exceptions box, type the fully qualified domain names of all the local servers, and then click OK three times.
NoteYou can also configure Internet Explorer to bypass the proxy server by modifying the REG_BINARY field in the following registry key: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections\SavedLegacySettings. This registry entry will be present and will be used by the Webclient even when the Internet Options dialog and the HKCU and DEFAULT registry keys show that the proxy is disabled.

Method 3: Change the order of network providers

  1. On the desktop, right-click My Network Places, and then click Properties.
  2. On the Advanced menu, click Advanced Settings.
  3. On the Provider Order tab, in the Network Providers list, click Web Client Network.
  4. Press DOWN ARROW so that Web Client Network is the last provider in the list, and then click OK.


Alternatively, you can change the network provider order in the registry. The registry entry is HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\NetworkProvider\Order\ProviderOrder. The default value of this entry is RDPNP,LanmanWorkstation,WebClient.

Method 4: Install the relevant hotfixes

If you installed Windows XP SP1 in Method 1, there is a more recent version of Webclient.dll available. For more information about installing the latest version of WebClient, click the following article number to view the article in the Microsoft Knowledge Base:
824383   (http://support.microsoft.com/kb/824383/ ) Error message when you try to copy a file by using WebDAV to a WebDAV server from a Windows XP-based computer
After you install this fix, set the value of the ServerNotFoundCacheLifeTimeInSec registry entry. To do this, follow the steps in the "Part 2" section of the following Microsoft Knowledge Base article:
823372  (http://support.microsoft.com/kb/823372/ ) Your Word documents take a long time to open when they have attached templates

Method 5: Adjust the installation of Internet Explorer

If you use the Internet Explorer Administration Kit to customize, deploy, and manage your installations of Internet Explorer 6, and if you have deployed Internet Explorer set on the .DEFAULT registry hive, you can use this method to resolve this behavior.

The WebClient service uses the .DEFAULT registry setting. Each WebClient request is sent to the proxy. The proxy request eventually times out.

When a Windows XP-based computer starts, it applies the computer policy file.
  1. The Multiple UNC Provider (MUP) is notified that the client has to connect to domaincontroller1.domain.com, or just a NetBIOS name of the logon server. Available redirectors are informed.
  2. WebClient tries to handle the request.
  3. WinInet loads and reads the proxy configuration from the registry:
    HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    ProxyEnable
    ProxyOverride
    ProxyServer
  4. If these three keys are set to use a proxy server, WinInet sends request to the proxy server. This may time out and fail. If it does, the WebClient service returns a negative response to the MUP.
In this case, you can work around by providing the domain controller NetBIOS name for the ProxyOverride value.

Note Depending on the name that is seen in the WebDAV request, this may also be the domain name for the internal domain.

The following is an example:
	"ProxyEnable"=1
	"ProxyServer"="http://ProxyServername:PortNumber"
	"ProxyOverride"="*.intranet; domaincontroller1;*.domain.com;10.10.*;<local>"
In this example, ProxyServername is the name of your proxy server, and PortNumber is the TCP port number for HTTP. The port number is typically 80 or 8080.
Collapse this tableExpand this table
KeyValue
ProxyEnable0 = Manual proxy detection is disabled. 1 = Manual proxy detection is enabled.
ProxyServerThe name and the port of the proxy server.
ProxyOverrideThe Domain Name System (DNS) addresses, separated by semi-colons, that should not be passed on to the proxy server. You can use the value <local> to bypass the proxy server for local addresses. If you include this value, it must be the final value in the string.
Note For the current user, the registry location is as follows:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
The entries of the proxy exception list are stored in the ProxyOverride value. To add new values to this list, follow these steps:
  1. In Internet Explorer, click Tools, and then click Internet Options.
  2. Click the Connections tab, and then click LAN Settings.
  3. Click Advanced.
  4. In the Exceptions box, type the appropriate information.
Note You can see the values of these keys in a WinMSD report under Internet Settings in the Connectivity section of Internet Explorer. You can also use the Microsoft Internet Explorer Administration Kit (IEAK) to configure proxy server settings on client computers.

For additional information about IEAK, visit the following Microsoft Web site:
http://technet.microsoft.com/en-us/ie/bb219517.aspx (http://technet.microsoft.com/en-us/ie/bb219517.aspx)
Note When a .pac file is used, WebDAV requests are generated if the .pac file includes the following:
function FindProxyForURL(http://services.support.microsoft.com/url, host)
{
}

You can modify the .pac to avoid WebDAV traffic:
function FindProxyForURL(http://services.support.microsoft.com/url, host)
{if (shExpMatch(host, "DCNAME*")) {                
     return "DIRECT";                                 
 } 

WORKAROUND

To work around this behavior, try either of the following solutions:
  • If it is possible, stop the service that listens on TCP port 80 on the domain controller or on the file server.
  • Disable the WebClient service on the Windows XP client.
To examine the status of the WebClient service on a WebDAV client computer, or to disable the WebClient service on a WebDAV client computer, follow these steps:
  1. Click Start, point to All Programs, point to Administrative Tools, and then click Computer Management.
  2. In the details pane, double-click Services and Applications.
  3. Double-click Services.
  4. Right-click WebClient, and then click Properties.
  5. Click the General tab.
  6. In the Startup type list, click Disabled.
  7. Click Apply, and then click OK.
Note You can disable the WebClient service as long as you do not have to modify or write files on Web Distributed Authoring and Versioning (WebDAV) servers.

Windows 2000 does not implement the WebClient service. By default, Windows Server 2003 has the WebClient service turned off. For more information about disabled services, click the following article number to view the article in the Microsoft Knowledge Base:
812519  (http://support.microsoft.com/kb/812519/ ) Services that are turned off by default in Windows Server 2003
There are some alternatives to WebClient. If you are running Windows XP, follow these steps:
  1. Disable the WebClient service.
  2. Install a program that uses Web folders. For example, install Microsoft Office XP or a later version.
  3. Delete your original network place.
  4. Create a new network place.
For more information about WebDAV and WebClient, click the following article number to view the article in the Microsoft Knowledge Base:
817929  (http://support.microsoft.com/kb/817929/ ) Files do not appear when you use Web Distributed Authoring and Versioning (WebDAV) to add a network place shortcut to a Windows SharePoint Services Web site

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

The WebClient service enables Windows-based programs to create, access, and modify Internet-based files using Win32 APIs. If this service is stopped, these functions are not available.

Turning off WebClient service stops the WebDAV redirector. You will not be able to use command-line commands such as net use, dir, copy, and rename to a Web server. You cannot use Add Network Place to add a Web DAV location. You cannot use Publishing Wizard to publish to MSN Communities. However, you can still continue to use servers that support the Server Message Block (SMB) protocol.

In Windows XP and later versions, the Windows file redirector has a built-in WebDAV client. Microsoft Office 2000 and Microsoft Office XP and Microsoft Office System 2003 have built-in WebDAV redirectors that work independently from the WebClient service.

Windows XP WebDAV Redirector

Windows XP includes the new WebDAV redirector component. With the WebDAV redirector component, programs that run on Windows XP can connect to the Internet, and can natively read and write data on the Internet. The WebDAV protocol is an extension to HTTP that lets data be written to HTTP targets such as the Microsoft MSN Web Communities. The WebDAV redirector provides file system-level access to these servers like the existing redirector provides access to SMB and Common Internet File System (CIFS) servers.

One way that you can access a WebDAV share is to use the net use command. For example, you can use the following command at the command prompt: NET USE * http://webserver/davscratch

To connect to an MSN Community, use http://www.msnusers.com/yourcommunityname/files/ as the target. The credentials you must use are your Microsoft .NET Passport credentials. Enter these details in the Connect Using Different User Name dialog box if you are using a mapped network drive, or use the /u: switch with the net use command. For example, you can use the following command at the command prompt: NET USE http://www.msnusers.com/yourname/files /u:yourpassportaccount@hotmail.com

Windows XP

The WebClient service is used if you connect a Web Folders without specifying a port. For example, if you use the "http://webserver/davscratch" URL, a network trace shows something that is similar to the following in the HTTP header:
 
  HTTP: User-Agent = Microsoft-WebDAV-MiniRedir/5.1.2600

Microsoft Office

When you use the syntax that includes a port number, you connect with Office WebDAV. For example, if you use the "http://webserver:80/davscratch" URL, a network trace shows something that is similar to the following:
HTTP: User-Agent = Microsoft Data Access Internet Publishing Provider DAV 

Note This may or may not show as "HTTP" traffic in Network Monitor because the proxy port can vary.

Notes

The following describes some of the known interoperability issues with WebDAV:
  • By default on Windows Server 2003, the WebDAV client is not enabled for security reasons. You have to enable the WebClient service.
  • Using Microsoft Office 2000 to connect to a Windows WebDAV share is only supported if Office 2000 is running on Windows 2000 or earlier operating systems. Using Office 2000 running on Windows XP-based computer to connect to a Windows WebDAV share is not supported.
  • When you use Microsoft Office on a Windows XP-based computer, use the Office WebDAV redirector instead of the Windows XP file redirector. Generally, when you use Microsoft Office products, it is best to use files that are represented by their HTTP names instead of their UNC paths. For example, use "http://Device Name/Virtual Root/File Name" instead of "\\Device Name\Virtual Root\File Name."

Disabling the WebClient does not affect Internet browsing. The WebClient is used only for Web Distributed Authoring and Versioning (WebDAV) connections.

When the Universal Naming Conventions (UNC) file name is used, the redirector will use SMB, WebDAV, or a combination of the two, depending on what is available on the server.

When an application tries to open a file that exists on a network, the I/O manager passes the request to a system component that is named the Multiple UNC Provider (MUP). MUP sits logically above all the redirectors. When a network path is passed to MUP, it polls all the registered redirectors to determine whether they understand the path. The redirectors in turn contact the server to establish if the path is valid for the specific protocol. If the server can satisfy the connection, the redirector will return success back the MUP. If not, the redirector returns a failure. All the future file I/O requests for this file are passed to the redirector that accepted the path. If more than one redirector accepts the path, MUP picks the one with the highest priority, as defined in the registry. For more information about problems with multiple redirectors, click the following article number to view the article in the Microsoft Knowledge Base:
171386  (http://support.microsoft.com/kb/171386/ ) Connectivity delay with multiple redirectors installed

URLScan blocks WebDAV requests

To learn more about URLScan, visit the following Microsoft Web site:
http://technet.microsoft.com/en-us/security/cc242650.aspx (http://technet.microsoft.com/en-us/security/cc242650.aspx)

Registry setting for timeouts

The WebClient service maintains a list of non-DAV servers (negative cache) that have been contacted in the last 60 seconds. If the server is found in this list, a fail is returned immediately without going on the network. The time a server remains in this list can be modified by changing the value of the ServerNotFoundCacheLifeTimeInSec registry entry.

Note If the \HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters\ServerNotFoundCacheLifeTimeInSec registry entry does not exist, create the entry.
Type: REG_DWORD
Value: Default 60 (Decimal)
No maxium and no minimum value


RequestTimeoutInSec represents the number of seconds that WebDAV waits for WinInet after issuing a request such as “Get file” or “Put file.”
\HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MRxDAV\Parameters\RequestTimeoutInSec
Type: REG_DWORD
Value: Default 600 (Decimal)

REFERENCES

For more information about related topics, click the following article numbers to view the articles in the Microsoft Knowledge Base:
812924   (http://support.microsoft.com/kb/812924/ ) Access to Windows NT 4.0 or Windows 2000 share may stop responding
312181   (http://support.microsoft.com/kb/312181/ ) Long delays when you open resources on a DFS share
171386  (http://support.microsoft.com/kb/171386/ ) Connectivity delay with multiple redirectors installed
271361  (http://support.microsoft.com/kb/271361/ ) How to disable Internet Explorer automatic proxy caching
320507  (http://support.microsoft.com/kb/320507/ ) Internet Explorer does not retry bad proxy server for 30 minutes
810401  (http://support.microsoft.com/kb/810401/ ) "Local device name is already in use" error message after you interrupt a "NET USE" command
812924  (http://support.microsoft.com/kb/812924/ ) Access to Windows NT 4.0 or Windows 2000 share may stop responding
817929  (http://support.microsoft.com/kb/817929/ ) Files do not appear when you use Web Distributed Authoring and Versioning (WebDAV) to add a network place shortcut to a Windows SharePoint Services Web site
819961  (http://support.microsoft.com/kb/819961/ ) How to configure client proxy server settings by using a registry file
823372  (http://support.microsoft.com/kb/823372/ ) Your Word documents take a long time to open when they have attached templates
826286  (http://support.microsoft.com/kb/826286/ ) New user cannot access the Internet and proxy settings are blank
829909  (http://support.microsoft.com/kb/829909/ ) Windows XP stops responding when you connect to a shared folder
830561  (http://support.microsoft.com/kb/830561/ ) Documents that have attached templates take a long time to open in Word 2002 and in Word 2003
317506  (http://support.microsoft.com/kb/317506/ ) You may not be able to log on to the domain with VPN if a Winsock proxy is enabled
262981  (http://support.microsoft.com/kb/262981/ ) Internet Explorer uses proxy server for local IP address even if the "Bypass proxy server for local addresses" option is turned on
209252  (http://support.microsoft.com/kb/209252/ ) Maximum number of characters that can be specified in the proxy exceptions list
For more information about WebDAV, visit the following Microsoft Web site:
http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/844f5e01-4b9e-4dac-897e-2a0bb33f28af.mspx (http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/844f5e01-4b9e-4dac-897e-2a0bb33f28af.mspx)

APPLIES TO
  • Microsoft Windows XP Professional
  • Microsoft Windows XP Professional SP1
  • Microsoft Windows XP Tablet PC Edition
Keywords: 
kbprb KB832161
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