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PM03348: CICS CLOSES A SOCKET ON BEHALF OF AN APPLICATION BUT INCORRECTLY SENDS A KEEPALIVE HEADER BACK IN A RESPONSE.

A fix is available

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APAR status

  • Closed as unreproducible.

Error description

  • Requests coming into CICS through TCPIP Sockets fail because the
    connection is closed.
    After reviewing the auxtrace, you can see that the last EXEC
    CICS instruction before the application returned control back to
    DFHWBBLI was an EXEC CICS WEB-SEND. One of the parameters on the
    WEB-SEND is CLOSESTATUS which has specified 741 for CLOSE.
    Further down in the auxtrace, you can see CICS sending out the
    response. Within the header information, you can see
    connection:close. The header looks as follows:
    HTTP/1.1 200 OK..Server: IBM_CIC
    S_Transaction_Server/3.1.0(zOS).
    .Date: Thu, 10 Dec 2009 16:45:00
     GMT..Content-Length: 0000000000
    01087..Connection: Close..
    After CICS sends these bytes of data, it then sends another x'18
    bytes of data for a connection:keepalive header as shown below.
    Connection: Keep-Alive..
    .
    CICS should not be sending a Keep-Alive header if it is going to
    close the socket on behalf of the application. This keep-alive
    header could cause the client to try to reuse the previous
    connection rather than a new one causing it to never reach CICS.
    

Local fix

  • Additional Key Words:
    kixrevswm
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All.                                         *
    ****************************************************************
    * PROBLEM DESCRIPTION: CICS adds a Connection: Keep-Alive      *
    *                      header when an application includes     *
    *                      the CLOSE option on EXEC CICS WEB       *
    *                      SEND.                                   *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    A client application is issuing HTTP requests to CICS.
    The server application issues EXEC CICS WEB SEND CLOSE.
    In response to this CICS inserts both "Connection: close"
    and "Connection: keep-alive" headers in the HTTP response.
    CICS closes the connection after sending the HTTP response.
    The presence of "Connection: keep-alive" causes the client
    to try to reuse the connection for the next request.
    This fails as the connection has been closed by CICS.
    

Problem conclusion

Temporary fix

  • FIX AVAILABLE BY PTF ONLY
    

Comments

  • DFHWBSR has been altered so that CICS does not automatically
    insert a "Connection: keep-alive" header when EXEC CICS WEB
    SEND includes the CLOSE option.
    

APAR Information

  • APAR number

    PM03348

  • Reported component name

    CICSTS V3 Z/OS

  • Reported component ID

    5655M1500

  • Reported release

    400

  • Status

    CLOSED UR3

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2009-12-11

  • Closed date

    2010-01-25

  • Last modified date

    2010-02-01

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

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

    UK53794

Modules/Macros

  •    DESWBAP  DESWBDM  DESWBRQ  DESWBRQF DESWBSR
    DESWBXM  DFHWBAP  DFHWBAPF DFHWBDM  DFHWBRQS DFHWBSR  DFHWBXM
    

Fix information

  • Fixed component name

    CICSTS V3 Z/OS

  • Fixed component ID

    5655M1500

Applicable component levels

  • R400 PSY UK53794

       UP10/01/27 P F001

Fix is available

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

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Document Information

Modified date:
01 February 2010