Application Support Note

ASN-2000-123

AXIS Diplomat 2000 - Windows Registry Changes

Last Reviewed: 05 November 2004

Products affected: AXIS Diplomat 2000

Description: Registry changes made by AXIS Diplomat 2000 SETUP program when running with a Microsoft Windows 2000, Windows NT 4.x or Windows 9x based server.

When the AXIS Diplomat SETUP program is run (for either a server or client installation), the SETUP program (build level 5.561 and above) checks the presence and value of certain Windows registry to ensure that the system is correctly configured. This support note is provided for information only in order to outline AXIS Diplomat's usage of registry keys. It should not be necessary to make further registry changes manually.

If you are running AXIS Diplomat 2000 with a build level earlier than 5.561 we recommend that you upgrade to the current level re-running SETUP on your server and any client workstations.

NOTE: THE MODIFICATIONS DOCUMENTED IN THIS TSN NEED NO LONGER BE MADE MANUALLY AS THE AXIS DIPLOMAT 2000 SETUP PROGRAM NOW MAKES THESE REGISTRY CHANGES FOR YOU (kernel build level 5.561 and above). THE INFORMATION BELOW IS PROVIDED FOR REFERENCE ONLY.

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Systems AXIS cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved or provide support services to resolve such problems except on a consultancy basis. Use the Registry Editor at your own risk.

1. Windows NT 4.x Registry Changes

1.1 Keep Alive for TCP/IP

Due to a limitation of Microsoft's TCP/IP stack, applications such as AXIS Diplomat 2000 which rely on the integrity of the client-server link cannot control the required keepalive mechanism. The effect of this is that unless the following registry change is made a failed AXIS Diplomat 2000 client may not be detected by the server for two hours or more after the failure has occurred. It is therefore possible in some situations for the AXIS Diplomat database to become corrupt two hours before users are notified!

This registry change, applied to the Windows NT machine running as the AXIS Diplomat server, results in a delay of only five minutes in detecting failed clients but does affect ALL applications on the Windows NT Server which utilise IP keep alives. The change does NOT apply to client workstations running AXIS Diplomat 2000.

System managers who are concerned over affects on other TCP/IP applications running on the same server should consider upgrading to Windows 2000. The registry change does NOT apply to Microsoft Windows 2000 as improvements to the TCP/IP implementation in Windows 2000 allow AXIS Diplomat to control this facility automatically and effect the change only for the AXIS Diplomat services.

1.1.1 Start the Registry Editor (Regedt32.exe) and go to the following subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

1.1.2 On the Edit Menu, click Add Value and add the following:

Value Name: KeepAliveTime
Data Type: REG_DWORD
Data: 300000 dec.

The value of 300000 decimal represents the time in milliseconds (5 minutes) before TCP attempts to verify that an idle connection is still intact by sending a keep alive packet. The default value is 7200000 milliseconds (2 hours).

1.1.3 Reboot the Windows NT server for the configuration change to take affect.

1.1.4 If you wish to test that the keepalive mechanism is working, load the AXIS services on the Windows NT server and then load the AXIS Diplomat 2000 client on the server and run the User Status Enquiry function.

Now load a copy of AXIS Diplomat 2000 on a client workstation and then disconnect this workstation from the network (e.g. unplug the network cable). After approximately 5 minutes you should see the entry for that client disappear from the User Status Enquiry.

1.2 DOS Clients

If you intend to run any AXIS Diplomat 7.4 (DOS) clients from Windows or DOS based workstations you should also refer to support note ASN-074-115 for further recommended registry changes.

If you run AXIS Diplomat 7.4 (DOS) clients from DOS (or REAL/32) client workstations using Microsoft File and Print Services for NetWare (FPNW) 4.0 (for Windows NT 4.x) or 5.0 (for Windows 2000) the AXIS Diplomat 2000 SETUP program makes essential registry changes for you. This occurs automatically providing that Microsoft FPNW has already been installed when the AXIS Diplomat SETUP program is run. If you install Microsoft FPNW at a later date you must ensure that you re-run the AXIS Diplomat SETUP program after rebooting from Microsoft's FPNW installation process.

2. Windows 95 & 98 Registry Changes

2.1 Keep Alive for TCP/IP

NOTE: THE MODIFICATIONS DOCUMENTED IN THIS SECTION NEED NO LONGER BE MADE MANUALLY AS THE AXIS DIPLOMAT 2000 SETUP PROGRAM NOW OPTIONALLY MAKES THESE REGISTRY CHANGES FOR YOU (kernel build level 5.561 and above).

Due to a limitation of Microsoft's TCP/IP stack, applications such as AXIS Diplomat 2000 which rely on the integrity of the client-server link cannot control the required keepalive mechanism. The effect of this is that unless the following registry change is made a failed AXIS Diplomat 2000 client may not be detected by the server for two hours or more after the failure has occurred. It is therefore possible in some situations for the AXIS Diplomat database to become corrupt two hours before users are notified!

This registry change is applicable to Windows 98 machines and Windows 95 machines with the Microsoft Winsock 2 update installed (AXIS Diplomat does not support Windows 95 machines without this update) which are acting as the AXIS Diplomat server. The change results in a delay of only five minutes in detecting failed clients but does affect ALL applications on the Windows server which utilise IP keep alives. The registry change does NOT apply to client workstations running AXIS Diplomat 2000.

1.1.1 Start the Registry Editor (REGEDIT.EXE) and go to the following subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VxD\MSTCP

1.1.2 On the Edit Menu click New, String Value, and add the following:

Value Name: KeepAliveTime
Value Data: 300000

The value of 300000 decimal represents the time in milliseconds (5 minutes) before TCP attempts to verify that an idle connection is still intact by sending a keep alive packet. The default value is 7200000 milliseconds (2 hours).

NOTE: Microsoft knowledgebase article Q158474 (as at 28/11/2000) documents the KeepAliveTime registry entry as a DWORD value whereas article Q140325 documents this as a String value. Our tests show that the KeepAliveTime setting behaves correctly under both Windows 95 (Winsock 2) and Windows 98 as a string value. Setting this entry as a DWORD value appears to cause unpredictable results including the disconnection of non-idle sessions!

3. Further Information

TechBase article ASN-074-115 AXIS Diplomat 7.4 & Windows NT 4.x Servers - Recommended Registry Settings.
Microsoft Knowledgebase article Q120642 - TCP/IP & NBT Configuration Parameters for Windows NT and Windows 2000.
Microsoft Knowledgebase article Q140325 - How to Determine Loss of Client/Server Connection.
Microsoft Knowledgebase article Q158474 - Windows TCP/IP Registry Entries.

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