OA23179: INVALID SYSPLEX PORT USED. CONNECTION FAILS.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Error Description:
  The TCPIP profile was configured to use SYSPLEXPORTS on
  a VIPADISTRIBUTE statement.
  An application was assigned a sysplex port that was still in
  use. More specifically: the same sysplex port was assigned,
  1. A sysplex port associated with a VIPA address was assigned
  to a server application.
  2. The connection was closed, the server freed the sysplex port
  and the client went into TIME_WAIT.
  3. The server initiated another connection (possibly from
  another host but with the same VIPA address) and was assigned
  the previously freed port.
  4. The connection to the client is rejected since the old
  connection using the same IP address and port is still in
  TIME_WAIT.
  
  This is a timing problem related to the amount of time it takes
  to fully terminate a connection at the client (TIME_WAIT).
  
  
  In this case the TCP application was FTP.
  Symptoms at the server included:
  425 Can't open data connection.
  EZA1735I Std Return Code = 16425, Error Code = 00002
  
  This could occur with different symptoms for different
  applications.
  
  Verification Steps:
  A SYSTCPIP CTRACE with option XCF will show the same sysplex
  port freed and obtained within a short amount of time.
  Note the freeing and obtaining of the sysplex port could occur
  on different TCPIP stacks and may require traces on all stacks
  using the VIPA address. In addition activating the trace may
  change the timing such that the problem may not easily occur.
  A SYSTCPDA packet trace will show the associated connection
  failure.
  

Local fix

• Since this a timing problem, a second connection attempt is
  likely to succeed.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All using Sysplexports Distributed DVIPAs.   *
  ****************************************************************
  * PROBLEM DESCRIPTION: Connection to a distributed VIPA        *
  *                      fails to connect because port is        *
  *                      in use.                                 *
  *                      FTP 425 data connection error may       *
  *                      occur.                                  *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  This timing problem was caused by a port, for sysplexports
  distributed DVIPA, being reissued before the client
  had released the port.
  

Problem conclusion

• This problem was fixed in ISTFSVEF by incrementing the last
  port number before starting the search for available ports.
  This reduces the chance that the last port issued will be
  reissued as soon.
  ISTFSVPC was changed to release the last port assigned if the
  port numbers wrap.
  This is a logical route of OA19741.
  

Temporary fix

Comments

APAR Information

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

  OA19741

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

  UA38061

Modules/Macros

• ISTFSVEF ISTFSVPC
  

Fix information

• Fixed component name

  VTAM V4 MVS/ESA

• Fixed component ID

  569511701

Applicable component levels

• R190 PSY UA38061

     UP08/01/22 P F801

Fix is available

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