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PI78774: On Demand Router routes request to web module mapped with less specific virtual host match.


You can track all active APARs for this component.


APAR status

  • Closed as program error.

Error description

  • When there are multiple web modules that match a request
    equally well (same context root, uri, and both either
    or non-generic applications), the web module is mapped to
    less specific vhost and is sometimes selected when it is
    preferable to select the web module with the most specific
    vhost match. This routing mismatch causes the ODR to return
    404 error code.
    The preference for vhost matches from most specific to least
    specific is as follows: exact match on both host and port,
    match with wildcard port, wildcard host with port match,
    wildcard host and wildcard port match.

Local fix

  • Ensure that there are no equivalent web module matches for
    incoming requests

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server On Demand Router                     *
    * PROBLEM DESCRIPTION: An incoming request to the On Demand    *
    *                      Router that matches multiple web        *
    *                      modules with the same level of detail   *
    *                      may be mapped to a web module with a    *
    *                      less specific virtual host match.       *
    * RECOMMENDATION:                                              *
    When a request arrives at the On Demand Router it is matched
    with a web module using the virtual host as well as context
    root, and uri mapping of the web module mapped to that virtual
    host. A request will always be routed to the most specific web
    module context root and uri mapping. However, if the context
    root and uri mapping of multiple web modules are equal the
    request should be routed to the web module mapped to the most
    specific virtual host match. In the error case the web module
    selected was the first virtual host match with the most specific
    context root and uri mapping from the web module rather than the
    most specific virtual host map.

Problem conclusion

  • The problem code was corrected to select the most specific
    virtual host match when there are multiple equally good web
    module matches using context root and uri pattern. The most
    specific virtual host is selected using this criteria in
    descending order: (1) exact match on host and port, (2) exact
    match on host and wildcard on port, (3) wildcard on host and
    exact match on port, and (4) wildcard on host and wildcard on
    The fix for this APAR is currently targeted for inclusion in fix
    pack  Please refer to the Recommended Updates page for
    delivery information:

Temporary fix

  • Eliminate duplicate web module matches by providing more
    specific context root and uri mappings such that requests will
    match more specifically to only one web module.


APAR Information

  • APAR number


  • Reported component name


  • Reported component ID


  • Reported release


  • Status


  • PE




  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date


  • Closed date


  • Last modified date


  • 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


  • Fixed component ID


Applicable component levels

  • R700 PSY


[{"Business Unit":{"code":"BU053","label":"Cloud \u0026 Data Platform"},"Product":{"code":"SSUP64","label":"WebSphere Virtual Enterprise"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.0","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
18 October 2021