IT07956: USING ACCESS CONTROL LISTS IN A NETWORK ENVIRONMENT WITH PACKET FRAGMENTATION MIGHT RESULT IN THE INSTABILITY OF TCP CONNECTIONS

Fix packs for DataPower B2B Appliance version 6.0
Fix packs for DataPower Integration Appliance version 6.0
Fix packs for DataPower Service Gateway version 6.0
Fix packs for DataPower Service Gateway version 6.0.1
Fix packs for DataPower B2B Appliance version 6.0.1
Fix packs for DataPower Integration Appliance version 6.0.1
Fix packs for DataPower Service Gateway version 7.0
Fix packs for DataPower B2B Appliance version 7.0
Fix packs for DataPower Integration Appliance version 7.0
Fix packs for DataPower Gateway version 7.1

APAR status

• Closed as program error.

Error description

• When services using Access Control Lists are deployed in a
  network environment with IP packet fragmentation, packets might
  be dropped unexpectedly, which might result in broken TCP
  connections.  This is more likely to manifest with longer
  transfers, for example, when using the appliance for file
  transfer.
  

Local fix

• Disable/remove ACL.
  

Problem summary

• Affected are DataPower configurations with services using
  several distinct Access Control Lists to restrict the range of
  client IP addresses.
  
  In network environment with frequent or deterministic IP packet
  fragmentation, parts of fragmented packets might be unexpectedly
  dropped.  The packet loss might result in network delays or TCP
  connection breakdown.
  

Problem conclusion

• Fix is available in 6.0.0.15, 6.0.1.11, 7.0.0.8 and 7.1.0.5.
  
  For a list of the latest fix packs available, please see:
  http://www-01.ibm.com/support/docview.wss?uid=swg21237631
  

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

  DTAPWR B2B APL

• Fixed component ID

  DP905XB62

Applicable component levels

• R600 PSN

     UP

• R601 PSN

     UP

• R700 PSN

     UP

• R710 PSN

     UP