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IT12287: IMPROVE THE WAY MANAGED FILE TRANSFER PROTOCOL BRIDGE AGENTS HANDLE FTP REPLY CODES

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • MQ Managed File Transfer protocol bridge agents currently treat
    FTP Reply Codes as being the result of unrecoverable errors. If
    a file server returns an FTP Reply Code indicating that a
    problem has occurred while trying to write the last piece of
    file data,
    then the  protocol bridge agent will mark the managed transfer
    as
    "Failed".
    
    The FTP Specification states that FTP Reply Codes in the range
    4xx represent Transient Negative Completion replies, and that
    the action which resulted in the FTP Reply Code being generated
    should be retried.
    
    This APAR is being raised to add new logic to the protocol
    bridge agent to ensure that it will retry a managed transfer if
    a file server returned an FTP Reply Code in the 4xx range just
    after
    the last piece of file data has been written.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This new function affects users of MQ V8.0 Managed File Transfer
    protocol bridge agents that connect to file servers using either
    the FTP or FTPS protocol.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When an MQ Managed File Transfer protocol bridge agent is acting
    as a Destination Agent in a managed transfer, and is connecting
    to a file server using either the FTP or FTPS protocol, it will
    establish two connections to the file server:
    
    - A control connection. This is used by the Protocol Bridge
    Agent and the file server to initiate file transfers, and
    monitor their state.
    - A data connection, which is used to send the file data to the
    file server.
    
    If a file transfer is in progress, and the file server
    encounters an issue, it will send an FTP reply code indicating
    the nature of the issue to the protocol bridge. FTP reply codes
    in the 4xx range represent transient issues, while FTP reply
    codes in the 5xx range represent a permanent issues which will
    prevent the managed transfer from completing.
    
    APARs IT08384 and IT09538 introduced logic to the protocol
    bridge agent to ensure that if a file server sent either FTP
    reply code 425 or 426 to the agent after the last piece of file
    data had been written to the file server, the agent put the
    managed transfer into recovery. However, if a file server sent
    any other FTP reply code in the 4xx range, or the 5xx range, to
    the protocol bridge agent, the agent incorrectly assumed that
    the reply code had already been handled, and so ignored it. As a
    result of this, the transfer item that was being transferred
    when the issue occurred was marked as as being "Successful",
    even though the file was not successfully written by the file
    server.
    

Problem conclusion

  • The logic that was introduced to the protocol bridge agent as
    part of APARs IT08384 andIT09538 has been expanded to handle the
    other FTP reply codes in the 4xx range. These FTP reply codes
    are shown below:
    
    421 	Service not available, closing control connection. This
    may be a reply to any command if the service knows it must shut
    down.
    430 	Invalid username or password
    434 	Requested host unavailable.
    450 	Requested file action not taken.
    451 	Requested action aborted. Local error in processing.
    452 	Requested action not taken. Insufficient storage space
    in system. File unavailable (e.g., file busy).
    
    If a file server returns any of these FTP reply codes after the
    last piece of the file data has been written to the file server,
    the protocol bridge agent will put the managed transfer into
    recovery.
    
    The protocol bridge agent has also been updated so that, if the
    file server returns an FTP reply code in 5xx range after the
    last piece of file data has been written, the managed transfer
    is marked as "Failed". The FTP reply codes in the 5xx range that
    will cause a managed transfer to be marked as "Failed" in this
    situation are shown below for reference:
    
    501 	Syntax error in parameters or arguments.
    502 	Command not implemented.
    503 	Bad sequence of commands.
    504 	Command not implemented for that parameter.
    530 	Not logged in.
    532 	Need account for storing files.
    550 	Requested action not taken. File unavailable (e.g.,
    file not found, no access).
    551 	Requested action aborted. Page type unknown.
    552 	Requested file action aborted. Exceeded storage
    allocation (for current directory or dataset).
    553 	Requested action not taken. File name not allowed.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v8.0       8.0.0.5
    
    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

    IT12287

  • Reported component name

    WMQ MFT V8.0

  • Reported component ID

    5724H7252

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2015-11-16

  • Closed date

    2016-01-11

  • Last modified date

    2016-01-11

  • 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 V8.0

  • Fixed component ID

    5724H7252

Applicable component levels

  • R800 PSY

       UP

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Document Information

Modified date:
11 January 2016