PI68727: CSSMTP CONNECTION HANGS IN CLOSEWAIT WHEN CONNECTIDLE IS NONZERO

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The CSSMTP configuration file has a non-zero ConnectIdle value.
  Therefore, a CSSMTP thread does not immediately close its TCP
  connection when it finishes transmitting a mail file to the
  remote server.  Instead, the CSSMTP thread saves the TCP
  connection for reuse in case there is another mail file to
  process before the ConnectIdle interval expires.  During this
  wait, the remote server sends message "421 Exceeded allowable
  connection time, disconnecting" and closes the TCP connection.
  CSSMTP has no mechanism to detect this and remains waiting for
  either the next mail file or expiration of the ConnectIdle
  interval.  This causes the TCP connection to hang in CloseWait
  WLOXFER state.
  
  If TRMD detects the unhandled 421 message in the TCP receive
  buffer, then it issues a message similar to the following
  message:
  
  EZZ8662I TRMD TCP receive queue constrained entry
  logged: mm/dd/yyyy hh:mm:ss.xx , connid= nnnnnnnn , jobname=
  cssmtpjobname , lipaddr= ii.ii.ii.ii , lport= lllll ,
  ripaddr=ii.ii.ii.ii , rport= 25 , correlator=nn ,
  probeid= nnnnnnnn , sensorhostname= nnnnnnnn ,
  trigger=DataAge , dataage= nnn , bytesqueued= nn , queuesize=VL
  

Local fix

• Specify a ConnectIdle value of 0 or a ConnectIdle value that is
  less than the remote server's timeout interval.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of the IBM Communications Server for z/OS Version  *
  * 2 Release 1 and Release 2 IP: CSSMTP                         *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * CSSMTP's tcp connection hangs in CLOSEWAIT when ConnectIdle  *
  * is non-zero.                                                 *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The CSSMTP configuration file has a non-zero ConnectIdle value.
  Therefore, a CSSMTP thread does not immediately close its TCP
  connection when it finishes transmitting a mail file to the
  remote server.  Instead, the CSSMTP thread saves the TCP
  connection for reuse in case there is another mail file to
  process before the ConnectIdle interval expires.  During this
  wait, the remote server sends message "421 Exceeded allowable
  connection time, disconnecting" and closes the TCP connection.
  CSSMTP has no mechanism to detect this and remains waiting for
  either the next mail file or expiration of the ConnectIdle
  interval.  This causes the TCP connection to hang in CloseWait
  WLOXFER state.
  
  If TRMD detects the unhandled 421 message in the TCP receive
  buffer, then it issues a message similar to the following
  message:
  EZZ8662I TRMD TCP receive queue constrained entry
  logged: mm/dd/yyyy hh:mm:ss.xx , connid= nnnnnnnn ,
  jobname=cssmtpjobname , lipaddr= ii.ii.ii.ii , lport= lllll ,
  ripaddr=ii.ii.ii.ii , rport= 25 , correlator=nn , probeid=
  nnnnnnnn , sensorhostname= nnnnnnnn ,
  trigger=DataAge , dataage= nnn , bytesqueued= nn , queuesize=VL
  

Problem conclusion

• CSSMTP has been updated to simulataneously monitor the JES spool
  and the TCP connection socket while the TCP connection is idle.
  

Temporary fix

Comments

• ×**** PE17/06/23 FIX IN ERROR. SEE APAR PI81188  FOR DESCRIPTION
  ×**** PE17/06/26 FIX IN ERROR. SEE APAR PI81188  FOR DESCRIPTION
  

APAR Information

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

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

  UI46341 UI46342 PI84686

Modules/Macros

• EZAMLJES EZAMLSMT EZAMLMN  EZAMLCON EZAMLMSG
  

Fix information

• Fixed component name

  TCP/IP V3 MVS

• Fixed component ID

  5655HAL00

Applicable component levels

• R210 PSY UI46341

     UP17/06/01 P F705

• R220 PSY UI46342

     UP17/06/01 P F705

Fix is available

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