PQ69608; 4.0.2 - 4.0.5: Plug- in failover fails with
proxy firewall
Downloadable files
Abstract
The plug-in is not failing over as expected when a proxy
firewall is between the plug-in and the WebSphere® Application
Server.
Download Description
PQ69608 resolves the following problem:
USERS AFFECTED:
WebSphere Application Server V4.0 users of the Web server plug-in with a
proxy firewall in between the plug-in and the Application Server.
PROBLEM DESCRIPTION:
The plug-in was not failing over as expected when a proxy firewall is
between the plug-in and the Application Server.
The plug-in marks a server down when the connect() fails. However, when a
proxy firewall is in between the plug-in and the Application server, the
connect() will succeed even though the backend Application Server is down.
This causes the plug-in to not failover correctly to other Application
Servers.
Here is an example of how to specify the new attribute:
<ServerGroup Name="default_group">
<Server Name="default_server1" ExtendedHandshake="true">
<Transport Hostname="192.168.1.2" Port="9080" Protocol="http"/>
</Server>
</ServerGroup>
PROBLEM CONCLUSION:
The plug-in now performs some handshaking with the application server to
ensure that it is up before sending the request. This allows us to
failover in the event the Application server is really down. This is
specified using the ExtendedHandshake attribute for the Server element in
the plug-in configuration file (plugin-cfg.xml).
NOTES:
PQ69608 REQUIRES the latest WebSphere Application Server plug-in fix, such
as WAS_plugin_03-07-2003_4.0.x_cumulative_eFix_<OS>.tar or any
later.
This interim fix MUST be applied to the application server and ONLY for
configurations with a proxy firewall between the plug-in and the
Application Server.
This fix is included in WebSphere Application Server V4.0.6.