PI40941: TRUNCATED DNS RESPONSE CAUSES SIP THREADS TO BLOCK

8.5.5.7: WebSphere Application Server V8.5.5 Fix Pack 7
8.5.5.8: WebSphere Application Server V8.5.5 Fix Pack 8
8.5.5.9: WebSphere Application Server V8.5.5 Fix Pack 9
8.5.5.10: WebSphere Application Server V8.5.5 Fix Pack 10
8.5.5.11: WebSphere Application Server V8.5.5 Fix Pack 11
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21

APAR status

• Closed as program error.

Error description

• When a SIP application submits a DNS lookup which causes a
  switch between UDP and TCP, the request might hang
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server Session Initiation Protocol (SIP)    *
  *                  container                                   *
  ****************************************************************
  * PROBLEM DESCRIPTION: When a SIP application submits a DNS    *
  *                      lookup which causes a switch between    *
  *                      UDP and TCP transports, the request     *
  *                      may hang.                               *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When a SIP application submits a DNS lookup which causes a
  switch between the UDP and TCP transports (because of packet
  size), the code may hit an endless loop. The lookup requires
  multiple requests to occur and the current code switches back
  to UDP prematurely.
  

Problem conclusion

• We fixed the code so that when a switch to TCP must occur, we
  continue to use TCP for the duration of the DNS request.
  
  The fix for this APAR is currently targeted for inclusion in
  fix pack 8.5.5.7.  Please refer to the Recommended Updates
  page for delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

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

  WEBSPHERE APP S

• Fixed component ID

  5724J0800

Applicable component levels

• R700 PSY

     UP

• R800 PSY

     UP

• R850 PSY

     UP