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

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 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

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