IT17824: A CLIENT APPLICATION FAILS TO CONNECT TO A QUEUE MANAGER WITH ERROR AMQ9777(CHANNEL WAS BLOCKED) WHEN CLIENT SIDE EXIT IS USED

APAR status

• Closed as program error.

Error description

• A client application fails to connect to a queue manager with
  error AMQ9777: Channel was blocked.
  
  AMQ9777: Channel was blocked
  The inbound channel 'A.TO.B' was blocked from address 'abc
  (xxx.xxx.xxx.xxx)' because the active values of the channel
  matched a record configured with USERSRC(NOACCESS). The active
  values of the channel were 'CLNTUSER('.
  
  This error is reported when there is a usermap rule which maps
  CLNTUSER 'XYZ' to 'ABC' and when there is a addressmap rule that
  blocks all the address. Along with the above CHLAUTH rule,  when
  CONNAUTH and a client-side exit are used, MQ is unable to honor
  USERMAP rule. The CLNTUSER in this case is a MQCSP user.
  
  Along with the above CHLAUTH rule, when CONNAUTH and a
  client-side exit are used, MQ is unable to honor USERMAP rule.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users who use a client-side exit along with CHLAUTH and CONNAUTH
  rules.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When an exit is used in the client side (e.g: mqccred exit)
  along with CHLAUTH and CONNAUTH rules, IBM MQ was unable to
  assert the client user and hence was failing to honour a USERMAP
  rule.
  
  This resulted in valid user credentials being incorrectly
  rejected by the queue manager.
  

Problem conclusion

• IBM MQ code has been updated such that it is able to assert the
  right user so that it could honour the USERMAP rule.
  
  Fix for APAR IT12825 has to be included along with this.
  
  To have the queue manager use this new behaviour, set the
  ChlauthEarlyAdopt attribute under the Channels stanza to 'e' or
  'E',
  e.g.
  
  Channels:
     ChlauthEarlyAdopt=e
  
  Note that setting ChlauthEarlyAdopt to 'e' or 'E' when security
  exits are not in use will have the same effect as setting it to
  'y' or 'Y'.
  
  APAR IT18052 made further changes to the new ChlauthEarlyAdopt
  parameter and so it is recommended that users review the details
  of that APAR in combination with this one.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.7
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

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

  WMQ BASE MULTIP

• Fixed component ID

  5724H7251

Applicable component levels

• R800 PSY

     UP