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IT09538: PROTOCOL BRIDGE AGENT CAN MARK TRANSFER ITEM AS SUCCESSFUL EVEN THOUGH FTP SERVER HAS BECOME UNAVAILABLE OR UNRESPONSIVE

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APAR status

  • Closed as program error.

Error description

  • A WebSphere MQ Managed File Transfer Protocol Bridge Agent is
    acting as the destination agent for a managed transfer.
    
    While processing a transfer item within a managed transfer, the
    FTP Server the Protocol Bridge Agent is communicating with
    becomes slow to respond and is unable to accept file data for
    approximately 70 seconds. As a result of this, the Protocol
    Bridge Agent times out while trying to write the file data, and
    the destination file is not written to the file server. However,
    no errors are reported and the transfer item is marked as
    "Successful".
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects users of:
    
    - The WebSphere MQ V7.5 Managed File Transfer component.
    - The WebSphere MQ V8.0 Managed File Transfer component.
    
    who are using the Protocol Bridge Agent to connect to a file
    server using either the FTP or FTPS protocol.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When a WebSphere MQ Managed File Transfer Protocol Bridge Agent
    has been configured to connect to a file server using either the
    FTP or FTPS protocols, it uses the Apache Commons Net library to
    handle all of the communication with the file server. If the
    Protocol Bridge Agent is acting as the Destination Agent for a
    managed transfer, the Apache Commons Net library will establish
    two connections to the file server:
    
    - A control connection. This is used to initiate file transfers,
    and monitor their state.
    - A data connection, which is used to send the file data to the
    file server.
    
    When the Protocol Bridge Agent processes a transfer item within
    a managed transfer, it passes the file data for that transfer
    item to the Apache Commons Net library. The library then writes
    the file data to the file server asynchronously. This means that
    after the Protocol Bridge Agent has passed all of the file data
    to the Apache Commons Net library, it has to wait for the
    library to write the file data to the file server before it can
    determine if the transfer item was successful or not.
    
    If the file server became unresponsive or unavailable in between
    the Protocol Bridge Agent passing the last bit of file data to
    the Apache Commons Net library, and before the library had
    confirmed that the file data had been successfully written to
    the file server, then the Apache Commons Net library would
    either report an exception, or return FTP reply code 425, back
    to the Protocol Bridge Agent.. The Protocol Bridge Agent
    received this exception or reply code and incorrectly assumed
    that it had already been handled. As a result of this, the
    exception or reply code was ignored and the transfer item that
    was being transferred when the file server became unresponsive
    or unavailable was marked as as being "Successful", even though
    the file was not successfully written by the file server.
    

Problem conclusion

  • The Protocol Bridge Agent has been updated so that if a file
    server becomes unresponsive or unavailable in between the
    Protocol Bridge Agent passing the last bit of file data to the
    Apache Commons Net library, and before the library confirming
    that the file data had been successfully written to the file
    server, the Protocol Bridge Agent will put the transfer into
    recovery. If the property:
    
      logTransferRecovery=true
    
    has been set on the Protocol Bridge Agent, then a message,
    similar to the ones shown below. will be written to the Agent's
    output0.log file:
    
    BFGTR0030E: A recoverable I/O error has occurred during a write
    operation. The agent will attempt to recover the file transfer.
    The transfer ID is: . The error message is: BFGBR0064W: The
    server has terminated the connection. Exception: Read timed out
    
    BFGTR0030E: A recoverable I/O error has occurred during a write
    operation. The agent will attempt to recover the file transfer.
    The transfer ID is:  . The error message is: BFGBR0186W: The
    server has terminated the connection. The reply string sent back
    by the server was 'PB-CLOSE - aborted [ReplyString=425 Can't
    open data connection.]
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.5       7.5.0.6
    v8.0       8.0.0.4
    
    The latest available FTE maintenance can be obtained from
    'Fix List for WebSphere MQ File Transfer Edition 7.0'
    http://www-01.ibm.com/support/docview.wss?uid=swg27015313
    
    The latest available MQ maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT09538

  • Reported component name

    WMQ MFT

  • Reported component ID

    5724H7242

  • Reported release

    750

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2015-06-18

  • Closed date

    2015-08-28

  • Last modified date

    2015-08-28

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    WMQ MFT

  • Fixed component ID

    5724H7242

Applicable component levels

  • R750 PSY

       UP

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Document Information

Modified date:
28 August 2015