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DomainScan Server Monitoring
 
   
Trouble shooting
Tech doc #5

Revision v1.32

Last Update
June 4 2008

Published
July 17 2006

Affected versions
DomainScan Server Monitoring 7
DomainScan Pro 2.0+




In this document, common error situations and their possible solutions are described.

This document cannot answer all possible problems, and the solution in this document may not provide a solution for your particular problem, even though the symptoms may be described in this document. In this case, please contact GH Software for further help.

Scanning failures up
  • The DomainScan Pro Engine Service failed to start
  • The DomainScan Pro Engine service terminated unexpectedly


  • Most of the times, this is an issue with the security credentials that are used to run the service.

    User name or password not correct
    It might be that the username has been misspelled. In that case, the Windows Event log will display a message like 'Logon failure: unknown user name or bad password.'.
    To resolve the problem, simply enter the correct password.

    The user does not have sufficient rights to run a service
    If the user isn’t a member of a group that has the necessary rights to run a service, then the service will also terminate. To be on the safe side, then DomainScan Pro must be set to run either as: Local System Account or with a username from the administrators group.

    It is also essential that the user has Log on as a service rights in Windows. Otherwise, Windows will still terminate the service even if the user is a member of the ‘administrators’ group.

    To check whether or not the user has these rights, open the Group Policy editor in Windows and locate the Log on as a service policy entry, as seen below.


    If the user is not in this list, then enter the user and try to restart the service.

    Note: Both DomainScan Pro and the “Services” management console in Windows will automatically assign Log on as a service rights.

    Devices cannot be found up
    By default, DomainScan Pro relies on the Computer Browser service, which is installed and enabled by default on all Windows NT based operating systems.
    However, beginning with Windows XP, SP2 this service is blocked by the Windows Firewall by default. This situation means, that the Computer Browser Service cannot maintain the list of computers that are queried by DomainScan. The result is that DomainScan Pro cannot detect any computers.

    Symptoms
    • The initial scan never completes
    • DomainScan Pro completes, but cannot find any devices or domains
    • An installed software firewall may warn that a program is trying to connect to the internet.
    This section is only valid for DomainScan Pro prior to v2.5 / DomainScan Pro Light 6.2

    If the initial scan never completes and DomainScan Pro Engine is terminated, open the Windows registry, and navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\GH Software\DomainScan\Service entry, and check for the Engine_Step and Engine_Progress values. If both values are 2 then DomainScan Pro is trying to communicate with the Computer Browser service.

    If the Computer Browser service doesn’t reply in a few minutes (15 minutes during the initial scan, and 5 minutes hereafter), then the watchdog service (DomainScan Pro Service Control) will terminate DomainScan Pro Service due to the fact that it believes that DomainScan Pro Service has entered a non-recoverable situation (see Techdoc 1).

    DomainScan Pro will be restarted automatically within a few minutes, but chances are that the same situation occurs again.

    Resolution

    One can do a manual check to whether or not the Host system has the necessary rights by executing the following command in a Command Prompt:


    This command will prompt Windows to show its list with known computers, and should at least return one device name – the name of itself.

    However, if the command fails, with an error similar to the one in the picture above, then DomainScan Pro will not be able to get a list of computers to scan.

    The 'net view' command will most likely fail if the Computer Browser service is not running, or if Windows is protected by a firewall.
    If Windows Firewall (XP, Vista) is active, then it is required that the File And Printer Sharing exception is added to the firewall.

    Alternatively, one can also execute this command (net view \\127.0.0.1) in the Command Prompt, which will list all known shares for the server. This command will also fail, if the network browser is not working properly.

    Summary

    Make sure that:
    The Computer Browser Service is running
    File And Printer Sharing is allowed by the Windows Firewall
    If you're running Windows Vista or Windows Server 2008 - see Techdoc 8

    Notes
      If the initial scan completes, but without finding anything, it is most likely due to a blocking firewall.

      One can get around this problem by creating Device Lists

      The problem is usually limited to computers that are not a member of an Active Directory, due to the fact that the list is then supplied by the directory.

      The problem also occur if DomainScan Pro is set not to use Windows Network (which can be set in Preferences -> Discovery).

      For help regarding the Computer Browser service, please consult Microsoft documentation and the documentation that is provided by your firewall manufacturer, in case that firewall is present.


    Very few devices up
  • The number of detected devices is significantly lower after a server restart

  • This situation occur if
    • DomainScan Pro Service is installed on an Active Directory server
    • There are more than one browse master
    If DomainScan Pro is installed on an Active Directory domain controller, then Windows will flush the list of online computers before restarting. And due to the fact that it takes a few minutes to rebuild the list, after the server has been restarted, then DomainScan Pro may receive an incomplete list of computers, and therefore report that there are fewer computers online that in reality.
    However this situation is self-healing, due to the fact that the list will be correct within a few minutes, which means that the 2nd or 3rd scan after a system restart should be correct again.

    Also, if there is more than one browse master, then the list of devices that are reported to DomainScan Pro by the Computer Browser service may be incomplete. But once the duplicate browser has been removed, and then the problem will be fixed automatically in a few minutes.


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