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Windows Terminal Server clients that are running a Citrix Metaframe client may intermittently not be able to connect to a Windows Base Terminal Server 4.0-based computer. However, later attempts to connect may work.
When two clients try to connect at the same time and the clients have a different network latency, Tdtcp.sys may select the incorrect endpoint. The first client over a slower link tries to set up a TCP connection by sending a Sync packet. The second client does the same, and the three-way handshake is completed before the first client has completed their three-way handshake. However, Tdtcp.sys selects the unfinished connection to put into a endpoint (client 1) instead of client 2. When a connection is seen by Citrix, it sends the text ICA to the client over the newly-created connection. This fails because the connection is not established, and when client 1 sends the packet to complete the three-way handshake, the Terminal server sends a reset.
Service Pack Information
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
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 Windows 2000 or Windows NT 4 service pack that contains this hotfix.
To resolve this problem immediately, 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:
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 tables. 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 ----------------------------------------------------- 14-Mar-2003 13:37 5.0.2195.6685 19,000 Tdtcp.sys
Windows NT 4.0
Date Time Version Size File name --------------------------------------------------------- 27-Feb-2003 07:16 4.0.1381.33546 18,520 Tdtcp.sys 27-Feb-2003 07:16 4.0.1381.33546 18,680 Tdipx.sys 27-Feb-2003 07:16 4.0.1381.33546 17,112 Tdnetb.sys 27-Feb-2003 07:16 4.0.1381.33546 16,280 Tdspx.sys
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.
The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.