PK86480: TCPIP DEVICE CONNECTED TO CICS AUTOMATICALLY EVEN THOUGH IT WAS NOT SET UP TO DO SO

APAR status

• Closed as fixed if next.

Error description

• The customer has TN3270 terminal emulators connecting to
  the TCPIP stack on z/OS.  Normally, they receive the
  Communication Server's (VTAM's) welcome screen (MSG10) first.
  Then, they choose what application they want to connect to.
    Intermittently, a user is automatically connected to a
  CICS region first.  They don't see the MSG10 screen first.
  They don't have a chance to make a selection.
  The first screen they see is CICS' Goodmorning Message.
  .
    CICS messages for the affected terminal are as follows:
  <><><><><><><><><><><><><><><><><><-><><><><><><><><><><><><><>
  DFHZC6907 Autoinstall starting for netname ABCDEFGH.
          Network qualified name is MYNET.ABCDEFGH.
  DFHZC6908 Autoinstall in progress for netname ABCDEFGH.
          TN3270 IP address is 01.23.456.789:1234
  DFHZC5966 INSTALL started for TERMINAL (  ABCD)
  DFHZC6935 Autoinstall for terminal ABCD with netname ABCDEFGH
          using model or template MYMOD successful.
  DFHZC3462 ABCD CSNE Node ABCDEFGH session terminated.
  NQNAME    ABCD,CSNE, 9:27:48,MYNET   ABCDEFGH
  .
  DFHZC3461 ABCD CSNE Node ABCDEFGH session started.
  NQNAME    ABCD,CSNE, 9:30:05,MYNET   ABCDEFGH
  TNADDR    ABCD,CSNE, 9:30:05,98.76.543.21:9876
  .
  DFHZC3477 ABCD CSNE Cleanup  received.
  NQNAME   ABCD,CSNE, 9:30:34,MYNET   ABCDEFGH
  DFHZC3437 ABCD CSNE Node ABCDEFGH action taken:
          CLSDST ABTASK ABSEND ABRECV
  DFHZC3462 ABCD CSNE Node ABCDEFGH session terminated.
  NQNAME   ABCD,CSNE, 9:30:34,MYNET   ABCDEFGH
  DFHZC5966 DELETE started for TERMINAL (  ABCD) .
  DFHZC6966 Autoinstall delete for terminal ABCD
          with netname ABCDEFGH was successful.
  <><><><><><><><><><><><><><><><><><-><><><><><><><><><><><><><>
    Matching these messages to
  - TCPIP messages
  - the customer's description of the error
  - and CICS code
  showed the the following set of events:
  .
   1) User1 connected to VTAM
     was assigned netname ABCDEFGH
     and got the MSG10 screen
   2) User1 selected CICS.
   3) VTAM drove CICS' Logon exit
   4) CICS used the Autoinstall process to create termid ABCD.
   5) While CICS was building its control blocks,
     VTAM lost contact with User1's device.
     Because no session had started with CICS yet,
     VTAM did not drive
     the LOSTERM or the Network Services Error exits.
   6) CICS finished building the TCTTE
     and issued the OPNDST for netname ABCDEFGH.
   7) VTAM gave back a nonzero return code
     because ABCDEFGH was not currently assigned.
   8) CICS' OPNDST exit (DFHZOPX)
     returned the negative response to DFHZOPN.
   9) DFHZOPN at label TCZOPNS2 saw the nonzero return code,
     marked the TCTTE with TCTECSL
     and put it on the activate scan queue
     to request a SIMLOGON to try to recover the terminal.
     NOTE: CSNE DFHZNAC was not called for this error.
                The NEP did not have a chance to alter this.
  10) VTAM queued the SIMLOGON request for netname ABCDEFGH
    because it was not currently assigned.
  11) User2 connected to Comm Server
    and was assigned netname ABCDEFGH.
    VTAM saw the pending SIMLOGON to CICS
    and completed the logon request to CICS
    forcing the second user into a connection with CICS
    because that was where the first user had been.
  .
    CICS/Communication Server should not force a second user
  to follow in a previous user's path.
  .
    If it doesn't cause more problems than it fixes.
  CICS could remove the
       OI    TCTEICSL,TCTECSL    AND SIMLOGON REQD.
  instruction from label TCZOPNSH in DFHZOPN,
  and set up dynamic terminals to be deleted, instead.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: CICS queues unnecessary SIMLOGON after  *
  *                      session failure.                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  This is a straightforward problem where a terminal requests a
  session with CICS but then cancels the session before CICS has
  had a chance to send the BIND. The BIND subsequently fails
  (RPLUSNSI '0009'x ACTIVE SESSION GONE) and DFHZOPX cleans up the
  session (CLSDST). The problem is that DFHZOPX also sets up a
  queued SIMLOGON request. When the session eventually becomes
  available again the customer tries to logon to IMS. However the
  queued SIMLOGON to CICS is processed first and the customer is
  presented with the CICS Good Morning Message, when he was
  expecting the IMS screen.
  

Problem conclusion

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

• This APAR is being closed FIN (Fixed If Next). This closing code
  indicates that this problem will be resolved in any subsequent
  release of CICS after CICS Transaction Server for z/OS V4.1.
  This closing code has been agreed with the APAR submitter.
  .
  Defect26923 defect 26923 PEG
  

APAR Information

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

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

Fix information

Applicable component levels

• R400 PSN

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