An Attack on Port 1720 May Cause NetMeeting to Refuse Incoming Connections (315092)



The information in this article applies to:

  • Microsoft NetMeeting 3.01 for Windows 2000
  • Microsoft NetMeeting 3.01 for Windows NT 4.0
  • Microsoft NetMeeting 3.01 for Windows Millennium Edition
  • Microsoft NetMeeting 3.01 for Windows 98 Second Edition
  • Microsoft NetMeeting 3.01 for Windows 98
  • Microsoft NetMeeting 3.01 for Windows 95

This article was previously published under Q315092

SYMPTOMS

An attack on port 1720 may cause NetMeeting to refuse incoming connections after more than approximately 200 Transmission Control Protocol (TCP) connections are opened. If you apply the fix that is mentioned in the following Microsoft Knowledge Base article, this problem is not resolved:

273854 MS00-077: Denial of Service Can Occur with Microsoft NetMeeting

CAUSE

This problem occurs because of the way that NetMeeting handles TCP connections in the Callcont.dll dynamic link library.

RESOLUTION

To resolve this problem, obtain the latest service pack for Microsoft 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

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Microsoft Windows 2000 Service Pack 4.

Modification Type:MinorLast Reviewed:7/8/2005
Keywords:kbWin2kSP4fix kbAppCompatibility kbbug kbenv kbfix kbSecurity KB315092