Microsoft KB Archive/327027

= TN3270E Client Cannot Log on Unless Host Sends MSG10 Message =

Article ID: 327027

Article Last Modified on 2/22/2007

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APPLIES TO


 * Microsoft SNA Server 4.0
 * Microsoft SNA Server 4.0 Service Pack 1
 * Microsoft SNA Server 4.0 Service Pack 2
 * Microsoft SNA Server 4.0 Service Pack 3
 * Microsoft SNA Server 4.0 Service Pack 4
 * Microsoft Host Integration Server 2000 Standard Edition

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This article was previously published under Q327027



SUMMARY
Users cannot log on to a host application when using the 3270 Client in TN3270E mode if the host does not send a MSG10 message when the logical unit (LU) is activated.

This problem may also occur with third-party TN3270E emulators.



MORE INFORMATION
A supported feature that modifies the product's default behavior is now available from Microsoft, but it is only intended to modify the behavior that this article describes. Apply it only to systems that specifically require it. This feature may receive additional testing. Therefore, if the system is not severely affected by the lack of this feature, we recommend that you wait for the next Microsoft Host Integration Server 2000 that contains this feature.

To obtain this feature immediately, contact Microsoft Product Support Services. 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

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 --  15-Aug-2002  09:29  5.0.0.900    33,040  Cfgs3270.dll 15-Aug-2002 09:29  5.0.0.900    209,168 Sna3270.dll 15-Aug-2002 10:30  5.0.0.900    20,752  Snas3270.dll 15-Aug-2002 09:29  5.0.0.900    57,616  Tn3270.dll

NOTE: Because of file dependencies, the most recent fix that contains the preceding files may also contain additional files.

In many IBM mainframe environments, the virtual telecommunications access method (VTAM) is configured to allow unformatted system services (USS) messages to be sent to 3270 devices, including 3270 emulators. One of the most common USS messages is the USS MSG10 message, which is also known as the VTAM sign-on, greeting, or banner screen.

If configured, the MSG10 message is sent to a 3270 LU when the LU is activated and a SSCP-LU (System Services Control Point - Logical Unit) session is active. A MSG10 message typically contains some general information about the mainframe system, a list of applications, and a place to enter the name of the application to connect to.

In those environments that do not use a MSG10 message, the user must enter an unformatted logon string to actually connect to an application on the host system. The following is an example of an unformatted logon string that is used to connect to an application called CICS01:

logon applid=cics01

The TN3270E RFC does not specifically address the handling of unformatted logons. The handling of unformatted logons is left up to the vendors that provide TN3270E servers and emulators. To read about the TN3270 enhancements, click here.

With the 3270 Client (WIN3270.exe) in TN3270E mode, a user can enter data after TN3270E negotiations are complete. However, any data entered by the user at this time will be sent to the TN3270E server in a NVT_DATA message. The TN3270E server is expecting SSCP_LU_DATA messages at this point, so the NVT_DATA message that contains the unformatted logon string is discarded.

The result is that the user cannot log on to a host application in those environments that do not send MSG10 messages after the 3270 LU is activated. After you apply the update and you turn on the following configuration option, the 3270 Client in TN3270E mode will send SSCP_LU_DATA messages when TN3270E negotiations are complete. With this change, a user can enter an unformatted logon string to connect to host applications in the absence of a MSG10 message.

To enable this feature, add the following setting to the [SnaServerWin3270] section of the WIN3270.ini: DefaultSSCPLU=1 The WIN3270.ini is used to store the configuration settings for the 3270 Client. The WIN3270.ini is located in the user profile directories as listed in the following table.

Additional query words: HIS 2000

Keywords: kbhotfixserver kbqfe kbbug kbfix kbinfo kbqfe KB327027

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