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z/TPF debugger connection problem in Windows 7

Technote (FAQ)


I am using Windows 7 on my personal computer (PC). I successfully registered my program with the z/TPF debugger, but the z/TPF debugger session does not start. Why?


The Windows firewall on Windows 7 might block the z/TPF debugger, which prevents the z/TPF debugger session from starting. The CUD00003E error message might be issued on your z/TPF system. This message indicates that the z/TPF debugger was unable to connect to the workstation because of a timeout. The timeout is occurring because the firewall is blocking the z/TPF debugger.
In addition to the z/TPF debugger, the Windows 7 firewall might block other applications, such as TPF Operations Server and the FTP client.

Do one of the following actions:

  • Disable the Windows firewall on Windows 7. Complete the following steps:
    1. On the taskbar, click Start > Control Panel > System and Security > Windows Firewall
    2. In the Windows Firewall window, in the left panel under Control Panel Home, click Turn Windows Firewall on or off
    3. In the Customize Settings window, under Home or work (private) network location settings, click Turn off Windows Firewall (not recommended).
    4. Click OK.
  • Customize the Windows 7 firewall to accept the ports that are used by the z/TPF debugger and the TPF Operations Server native test environment.

For more information about disabling the Windows firewall, go to

For more information about customizing the Windows firewall, go to

Always ensure that your PC is compliant with security standards. For more information about addressing security issues, see your I/T support representative.

Related information

TPF Family Libraries

Document information

More support for: TPF

Software version: 1.1

Operating system(s): z/TPF

Reference #: 1619204

Modified date: 04 December 2012

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