Phantom Connection Count When Keep-Alive Connections Switch Host Header (321561)


The information in this article applies to:

  • Microsoft Internet Information Server 4.0
  • Microsoft Internet Information Services 5.0
This article was previously published under Q321561

SYMPTOMS

After you install the fix from the following Microsoft Knowledge Base article

319733 MS02-018: April 2002 Cumulative Patch for Internet Information Services

a Web site may return the following error message:
HTTP 403.9: Access Forbidden

CAUSE

If a single site is mapped to multiple Domain Name System (DNS) names and multiple users switch between different DNS names in that site, the connection count is distorted when a keep-alive connection connects to different host headers that are mapped to a single site. A phantom connection count is enumerated each time a connection switches host headers.

RESOLUTION

IIS 4.0

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem.

To resolve this problem immediately, download the fix by clicking the download link later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

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 fix 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
   ----------------------------------------------------
   30-Apr-2002  07:31  4.2.776.1  214,544  Adsiis.dll       
   30-Apr-2002  07:32  4.2.776.1  330,672  Asp.dll          
   30-Apr-2002  07:32  4.2.776.1   34,384  Clusiis4.dll     
   30-Apr-2002  07:31  4.2.776.1   55,392  Httpodbc.dll     
   30-Apr-2002  07:31  4.2.776.1   98,912  Iischema.dll     
   30-Apr-2002  07:30  4.2.776.1   63,984  Iislog.dll       
   30-Apr-2002  07:30  4.2.776.1  185,792  Infocomm.dll     
   30-Apr-2002  07:30  4.2.776.1   29,520  Iscomlog.dll     
   30-Apr-2002  07:31  4.2.776.1   38,256  Ssinc.dll        
   30-Apr-2002  07:31  4.2.776.1   25,360  Sspifilt.dll     
   30-Apr-2002  07:31  4.2.776.1  231,104  W3svc.dll        
   30-Apr-2002  07:30  4.2.776.1   88,032  Wam.dll

IIS 5.0

To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910 How to Obtain the Latest Windows 2000 Service Pack

The English version of this fix 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     Filename
   ------------------------------------------------------
   19-Apr-2002  23:08  5.0.2195.5624  348,944  W3svc.dll

WORKAROUND

To work around this problem if you have already applied MS02-018 to your Web server, follow these steps:
  1. Click Start, point to Programs, point to Administrative Tools, and then click Internet Services Manager.
  2. Right-click the Web site, and then click Properties.
  3. On the Web Site tab, click to select Unlimited Connections.NOTE: Make sure that you consider any licensing implications that may be involved when you change this property.

STATUS

Microsoft has confirmed that this is a problem in IIS 4.0 and 5.0. This problem was first corrected in Windows 2000 Service Pack 3.

MORE INFORMATION

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

272235 Internet Connector License Types for Windows 2000

Modification Type:MinorLast Reviewed:9/27/2005
Keywords:kbHotfixServer kbQFE kbbug kbfix kbWin2000sp3fix KB321561
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