FIX: Dialup connection does not disconnect Microsoft SQL Server even after timeout expires (327142)


The information in this article applies to:

  • Microsoft Data Access Components 2.7
  • Microsoft Data Access Components 2.7 SP1
This article was previously published under Q327142
Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SYMPTOMS

When you try to access a Microsoft SQL Server by using a dialup connection, you may notice that the dialup connection does not disconnect even after the timeout expires.

CAUSE

This behavior occurs because the network library DLL (DBNetLib.dll) sends keep-alive TCP/IP packets to Microsoft SQL Server to maintain the connection.

RESOLUTION

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel. 
     Date         Time   Version            Size    File name
   --------------------------------------------------------------
   26-Jul-2002  09:36  2000.81.9001.13    61,440  Dbnetlib.dll

STATUS

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

MORE INFORMATION

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

When you use the TCP/IP protocol to connect to your SQL Server server, in certain circumstances the DBNetlib DLL sets the KeepAliveTime registry setting and the KeepAliveInterval registry setting in the underlying TCP/IP socket layer with some hard-coded values. The hard-coded value for KeepAliveTime is 30,000 milliseconds and the hard-coded value for KeepAliveInterval is 1,000 milliseconds. If you do not have these registry subkeys (KeepAliveTime and KeepAliveInterval) in the following location, the DBNetLib DLL uses the default values: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer\Client\SuperSocketNetLib\Tcp
To change these default values (30,000 milliseconds and 1,000 milliseconds, respectively), add these registry subkeys, and then set their value.

REFERENCES

For additional information, visit the following Microsoft Developer Network (MSDN) Web sites:

Client and Server Net-Libraries
http://msdn.microsoft.com/library/en-us/architec/8_ar_cs_3flf.asp

Controlling Net-Libraries and Communications Addresses
http://msdn.microsoft.com/library/en-us/architec/8_ar_cs_9okz.asp

Modification Type:MinorLast Reviewed:10/11/2005
Keywords:kbHotfixServer kbQFE kbBug kbfix kbDialUp kbconnectivity kbQFE KB327142 kbAudDeveloper
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