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Using Web Server Plug-Ins With WebLogic Server

Installing and Configuring the Microsoft Internet Information Server (IIS) Plug-In

The following sections describe how to install and configure the Microsoft Internet Information Server Plug-In.

- Overview of the Microsoft Internet Information Server Plug-In

- Certifications

- Installing and Configuring the Microsoft Internet Information Server Plug-In

- Proxying Requests from Multiple Virtual Websites to WebLogic Server

- Sample iisproxy.ini File

- Creating ACLs Through IIS

- Using SSL with the Microsoft Internet Information Server Plug-In

- Proxying Servlets from IIS to WebLogic Server

- Testing the Installation

- Connection Errors and Clustering Failover

Overview of the Microsoft Internet Information Server Plug-In

The Microsoft Internet Information Server Plug-In allows requests to be proxied from a Microsoft Internet Information Server (IIS) to WebLogic Server. The plug-in enhances an IIS installation by allowing WebLogic Server to handle those requests that require the dynamic functionality of WebLogic Server.

You use the Microsoft Internet Information Server Plug-In in an environment where the Internet Information Server (IIS) serves static pages such as HTML pages, while dynamic pages such as HTTP Servlets or JavaServer Pages are served by WebLogic Server. WebLogic Server may be operating in a different process, possibly on a different host. To the end user—the browser—the HTTP requests delegated to WebLogic Server still appear to be coming from IIS. The HTTP-tunneling facility of the WebLogic client-server protocol also operates through the plug-in, providing access to all WebLogic Server services.

Connection Pooling and Keep-Alive

The Microsoft Internet Information Server Plug-In improves performance by using a re-usable pool of connections from the plug-in to WebLogic Server. The plug-in implements HTTP 1.1 keep-alive connections between the plug-in and WebLogic Server by re-using the same connection for subsequent requests from the same client. If the connection is inactive for more than 30 seconds, (or a user-defined amount of time) the connection is closed. The connection with the client can be reused to connect to the same client at a later time if it has not timed out. You can disable this feature if desired. For more information, see KeepAliveEnabled

Proxying Requests

The plug-in proxies requests to WebLogic Server based on a configuration that you specify. You can proxy requests either based on the URL of the request or a portion of the URL. This is called proxying by path. You can also proxy a request based on the MIME type of the requested file, called proxying by file extension. You can also use a combination of both methods. If a request matches both criteria, the request is proxied by path. You can also specify additional parameters for each of these types of requests that define additional behavior of the plug-in. For more information, see Installing and Configuring the Microsoft Internet Information Server Plug-In.

Certifications

The Microsoft Internet Information Server Plug-In is supported on Windows. Plug-ins are not supported on all operating systems for all releases. For information on platform support for specific versions of Microsoft Internet Information Server Plug-In, see Platform Support for WebLogic Server Plug-ins and Web Servers in Supported Configurations for WebLogic Server 7.0.

Installing and Configuring the Microsoft Internet Information Server Plug-In

To install the Microsoft Internet Information Server Plug-In:

1. Copy the iisproxy.dll file from the WL_HOME/server/bin directory of your WebLogic Server installation (where WL_HOME is the top-level directory for the WebLogic Platform and Server and contains the WebLogic Server installation files) into a convenient directory that is accessible by IIS. This directory must also contain the iisproxy.ini file that you will create in step 7.

2. Start the IIS Internet Service Manager by selecting it from the Microsoft IIS Start menu.

3. In the left panel of the Service Manager, select your website (the default is "Default Web Site").

4. Click the "Play" arrow in the toolbar to start.

5. Open the properties for the selected website by holding the right mouse button down over the website selection in the left panel.

6. In the Properties panel, select the Home Directory tab, and click the Configuration button in the Applications Settings section.

7. If you want to configure proxying by file extension (MIME type) complete this step. (You can configure proxying by path in addition to or instead of configuring by MIME type. See step 9. .)

   1. On the Mappings tab, click the Add button to add file types and configure them to be proxied to WebLogic Server.

   2. In the dialog box, browse to find the "iisproxy.dll" file.

   3. Set the Extension to the type of file that you want to proxy to WebLogic Server.

   4. Deselect the "Check that file exists" check box.

   5. Set the Method exclusions as needed to create a secure installation.

   6. When you finish, click the OK button to save the configuration. Repeat this process for each file type you want to proxy to WebLogic.

   7. When you finish configuring file types, click the OK button to close the Properties panel.

   Note: In the URL, any path information you add after the server and port is passed directly to WebLogic Server. For example, if you request a file from IIS with the URL:

   >     http://myiis.com/jspfiles/myfile.jsp

   it is proxied to WebLogic Server with a URL such as

   >     http://mywebLogic:7001/jspfiles/myfile.jsp

   Note: To avoid out-of-process errors, do not deselect the "Cache ISAPI Applications" check box.

8. In WebLogic Server, create the iisproxy.ini file.

   The iisproxy.ini file contains name=value pairs that define configuration parameters for the plug-in. The parameters are listed in General Parameters for Web Server Plug-Ins.

   Note: Changes in the parameters will not go into effect until you restart the "IIS Admin Service" (under services, in the control panel).

   BEA recommends that you locate the iisproxy.ini file in the same directory that contains the iisproxy.dll file. You can also use other locations. If you place the file elsewhere, note that WebLogic Server searches for iisproxy.ini in the following directories, in the following order:

   1. The same directory where iisproxy.dll is located.

   2. The home directory of the most recent version of WebLogic Server that is referenced in the Windows Registry. If WebLogic Server does not find the iisproxy.ini file there, it continues looking in the Windows Registry for older versions of WebLogic Server and looks for the iisproxy.ini file in the home directories of those installations.

   3. The directory c:\weblogic, if it exists.

9. If you want to configure proxying by path complete this step. ( In addition to proxying by file type, you can configure the Microsoft Internet Information Server Plug-In to serve files based on their path by specifying some additional parameters in the iisproxy.ini file.) Proxying by path takes precedence over proxying by MIME type.

   You can also proxy multiple websites defined in IIS by path. For more information, see Proxying Requests from Multiple Virtual Websites to WebLogic Server.

   To configure proxying by path:

   1. Place the iisforward.dll file in the same directory as the iisproxy.dll file and add the iisforward.dll file as a filter service in IIS (WebSite Properties —> ISAPI Filters tab —> Add the iisforward dll).

   2. Register .wlforward as a special file type to be handled by iisproxy.dll in IIS.

   3. Define the property WlForwardPath in iisproxy.ini. WlForwardPath defines the path that is proxied to WebLogic Server, for example: WlForwardPath=/weblogic.

   4. Set the PathTrim parameter to trim off the WlForwardPath when necessary. For example, using

      >     WlForwardPath=/weblogic
      >     PathTrim=/weblogic

      trims a request from IIS to Weblogic Server. Therefore, /weblogic/session is changed to /session.

   5. If you want requests that do not contain extra path information (in other words, requests containing only a host name), set the DefaultFileName parameter to the name of the welcome page of the Web Application to which the request is being proxied. The value of this parameter is appended to the URL.

   6. If you need to debug your application, set the Debug=ON parameter in iisproxy.ini. A c:\tmp\iisforward.log is generated containing a log of the plug-in's activity that you can use for debugging purposes.

10. Define the WebLogic Server host and port number to which the Microsoft Internet Information Server Plug-In proxies requests Depending on your configuration, there are two ways to define the host and port:

    - If you are proxying requests to a single WebLogic Server, define theWebLogicHost and WebLogicPort parameters in the iisproxy.ini file. For example:

      >     WebLogicHost=localhost
      >     WebLogicPort=7001

    - If you are proxying requests to a cluster of WebLogic Servers, define the WebLogicCluster parameter in the iisproxy.ini file. For example:

      >     WebLogicCluster=myweblogic.com:7001,yourweblogic.com:7001

      Where myweblogic.com and yourweblogic.com are instances of Weblogic Server running in a cluster.

11. Optionally, enable HTTP tunneling by following the instructions for proxying by path (see step 9 above), substituting the WebLogic Server host name and the WebLogic Server port number, or the name of a WebLogic Cluster that you wish to handle HTTP tunneling requests.

>     	WlForwardPath=*/HTTPClnt*

You do not need to use the PathTrim parameter.

Note: The only time you need to use HTTP-tunneling is when you connect through an applet through IIS/NES to WebLogic Server and and use http as the protocol instead of t3. (For example, http:// as the protocol in the provider URL instead of t3://.)

1. Set any additional parameters in the iisproxy.ini file. A complete list of parameters is available in the appendix General Parameters for Web Server Plug-Ins.

2. If you are proxying servlets from IIS to WebLogic Server and you are not proxying by path, read the section Proxying Servlets from IIS to WebLogic Server.

Proxying Requests from Multiple Virtual Websites to WebLogic Server

To proxy requests from multiple Websites (defined as virtual directories in IIS) to WebLogic Server:

1. Create a new directory for the virtual directories. This directory will contain dll and ini files used to define the proxy.

2. Copy iisforward.dll to the directory you created in step1.

3. Register the iisforward.dll for each Website with IIS.

4. Create a file called iisforward.ini. Place this file in the same directory that contains iisforward.dll. This file should contain the following entry for each virtual website defined in IIS:

   >     vhostN=websiteName:port
   >     websiteName:port=dll_directory/iisproxy.ini

   Where:

   - N is an integer representing the virtual website. The first virtual website you define should use the integer 1 and each subsequent website should increment this number by 1.

   - websiteName is the name of the virtual website as registered with IIS.

   - port is the port number where IIS listens for HTTP requests.

   - dll_directory is the path to the directory you created in step 1.

     For example:

     >     vhost1=strawberry.com:7001
     >     strawberry.com:7001=c:\strawberry\iisproxy.ini
     >     vhost2=blueberry.com:7001
     >     blueberry.com:7001=c:\blueberry\iisproxy.ini
     >     ...

5. Create an iisproxy.ini file for the virtual Websites, as described in step 8. in Proxying Requests. Copy this iispoxy.ini file to the directory you created in step 1.

6. Copy iisproxy.dll to the directory you created in step 1.

7. In IIS, set the value for the Application Protection option to high (isolated). If the Application Protection option is set to Medium(pooled), the iisproxy.dll that registered as the first website will always be invoked. In this event, all the requests will be proxied to the same WLS instances defined in the iisproxy.ini of the first website.

Sample iisproxy.ini File

Here is a sample iisproxy.ini file for use with a single, non-clustered WebLogic Server. Comment lines are denoted with the "#" character.

>     # This file contains initialization name/value pairs
>     # for the IIS/WebLogic plug-in.

>     WebLogicHost=localhost
>     WebLogicPort=7001
>     ConnectTimeoutSecs=20
>     ConnectRetrySecs=2

Here is a sample iisproxy.ini file with clustered WebLogic Servers. Comment lines are denoted with the "#" character.

>     # This file contains initialization name/value pairs
>     # for the IIS/WebLogic plug-in.

>     WebLogicCluster=myweblogic.com:7001,yourweblogic.com:7001
>     ConnectTimeoutSecs=20
>     ConnectRetrySecs=2

Note: If you are using SSL between the plug-in and WebLogic Server, the port number should be defined as the SSL listen port.

Creating ACLs Through IIS

ACLs will not work through the Microsoft Internet Information Server Plug-In if the Authorization header is not passed by IIS. Use the following information to ensure that the Authorization header is passed by IIS.

When using Basic Authentication, the user is logged on with local log-on rights. To enable the use of Basic Authentication, grant each user account the Log On Locally user right on the IIS server. Two problems may result from Basic Authentication's use of local logon:

- If the user does not have local logon rights, Basic Authentication does not work even if the FrontPage, IIS, and Windows NT configurations appear to be correct.

- A user who has local log-on rights and who can obtain physical access to the host computer running IIS will be permitted to start an interactive session at the console.

To enable Basic Authentication, in the Directory Security tab of the console, ensure that the Allow Anonymous option is "on" and all other options are "off".

Using SSL with the Microsoft Internet Information Server Plug-In

You can use the Secure Sockets Layer (SSL) protocol to protect the connection between WebLogic Server and the Microsoft Internet Information Server Plug-In. The SSL protocol provides confidentiality and integrity to the data passed between the Microsoft Internet Information Server Plug-In and WebLogic Server.

The Microsoft Internet Information Server Plug-In does not use the transport protocol (http or https) to determine whether the SSL protocol will be used to protect the connection between the proxy plug-in and the Microsoft Internet Information Server. In order to use the SSL protocol with the Microsoft Internet Information Server Plug-In, configure the WebLogic Server instance receiving the proxied requests to use the SSL protocol. The port on the WebLogic Server that is configured for secure SSL communication is used by the Microsoft Internet Information Server Plug-In to communicate with the Microsoft Internet Information Server.

Configuring SSL

To use the SSL protocol between Microsoft Internet Information Server Plug-In and WebLogic Server:

1. Configure WebLogic Server for SSL. For more information, see Configuring the SSL Protocol.

2. Configure the WebLogic Server SSL listen port. For more information, see Configuring the SSL Protocol.

3. Set the WebLogicPort parameter in the iisproxy.ini file to the listen port configured in step 2.

4. Set the SecureProxy parameter in the iisproxy.ini file to ON.

5. Set additional parameters in the iisproxy.ini file that define the SSL connection. For a complete list of parameters, see SSL Parameters for Web Server Plug-Ins

For example:

>     WebLogicHost=myweblogic.com
>     WebLogicPort=7002
>     SecureProxy=ON

Specifying Trust for the WL-Proxy-Client-Cert Header

The plug-in can encode users' identity certifications in the WL-Proxy-Client-Cert header and pass the header to WebLogic Server instances (see Proxying Requests to Another Web Server). A WebLogic Server instance uses the certificate information from that header, trusting that it comes from a secure source (the Plug-In), to authenticate the user. In previous releases of WebLogic Server, the default behavior was to always trust the WL-Proxy-Client-Cert header. Beginning with WebLogic Server 6.1 SP2, you need to explicitly define trust of the WL-Proxy-Client-Cert header. A new parameter, clientCertProxy, allows WebLogic Server to determine whether to trust the certificate header. For an additional level of security, use a connection filter to limit all connections into WebLogic Server (therefore allowing WebLogic Server to only accept connections from the machine on which the plug-in is running).

The clientCertProxy parameter has been added to the HTTPClusterServlet and Web applications.

For the HTTPClusterServlet, add the parameter to the web.xml file as follows:

>     <context-param>

>             <param-name>clientCertProxy</param-name>

>             <param-value>true</param-value>

>     </context-param>

For Web applications, add the parameter to the web.xml file as follows:

>     ServletRequestImpl context-param

>     <context-param>

>             <param-name>weblogic.httpd.clientCertProxy</param-name>

>             <param-value>true</param-value>

>     </context-param>

You can also use this parameter in a cluster as follows:

>     <Cluster ClusterAddress="127.0.0.1" Name="MyCluster"

>             ClientCertProxyHeader="true"/>

Proxying Servlets from IIS to WebLogic Server

You can proxy servlets by path if the iisforward.dll is registered as a filter. You would then invoke your servlet with a URL similar to the following:

>     http://IISserver/weblogic/myServlet

To proxy servlets if iisforward.dll is not registered as a filter, you must configure servlet proxying by file type.To proxy servlets by file type:

1. Register an arbitrary file type (extension) with IIS to proxy the request to the WebLogic Server, as described in step 7. under Installing and Configuring the Microsoft Internet Information Server Plug-In.

2. Register your servlet in the appropriate Web Application. For more information on registering servlets, see Configuring Servlets.

3. Invoke your servlet with a URL formed according to this pattern:

   http://www.myserver.com/virtualName/anyfile.ext

   where virtualName is the URL pattern defined in the <servlet-mapping> element of the Web Application deployment descriptor (web.xml) for this servlet and ext is a file type (extension) registered with IIS for proxying to WebLogic Server. The anyfile part of the URL is ignored in this context.

   Note:

   - If the image links called from the servlet are part of the Web Application, you must also proxy the requests for the images to WebLogic Server by registering the appropriate file types (probably .gif and .jpg) with IIS. You can, however, choose to serve these images directly from IIS if desired.

   - If the servlet being proxied has links that call other servlets, then these links must also be proxied to WebLogic Server, conforming to the pattern described in step 3.

Testing the Installation

After you install and configure the Microsoft Internet Information Server Plug-In, follow these steps for deployment and testing:

1. Make sure WebLogic Server and IIS are running.

2. Save a JSP file into the document root of the default Web Application.

3. Open a browser and set the URL to the IIS + filename.jsp as shown in this example:

   >     http://myii.server.com/filename.jsp

   If filename.jsp is displayed in your browser, the plug-in is functioning.

Connection Errors and Clustering Failover

When the Microsoft Internet Information Server Plug-In attempts to connect to WebLogic Server, the plug-in uses several configuration parameters to determine how long to wait for connections to the WebLogic Server host, and, after a connection is established, how long the plug-in waits for a response. If the plug-in cannot connect or does not receive a response, the plug-in attempts to connect and sends the request to other WebLogic Servers in the cluster. If the connection fails or there is no response from any WebLogic Server instance in the cluster, an error message is sent.

Figure 3-1 demonstrates how the plug-in handles failover.

Possible Causes of Connection Failures

Failure of the WebLogic Server host to respond to a connection request could indicate problems with the host machine, networking problems, or other server failures.

Failure of any WebLogic Server instance in the cluster to respond, could indicate that WebLogic Server is not running or is unavailable, a hung server, a database problem, or other application failure.

Failover with a Single, Non-Clustered WebLogic Server

If you are running only a single WebLogic Server, the plug-in only attempts to connect to the server defined with the WebLogicHost parameter. If the attempt fails, an HTTP 503 error message is returned. The plug-in continues trying to connect to WebLogic Server until ConnectTimeoutSecs is exceeded.

The Dynamic Server List

When you specify a list of WebLogic Servers in the WebLogicCluster parameter, the plug-in uses that list as a starting point for load balancing among the members of the cluster. After the first request is routed to one of these servers, a dynamic server list is returned containing an updated list of servers in the cluster. The updated list adds any new servers in the cluster and deletes any that are no longer part of the cluster or that have failed to respond to requests. This list is updated automatically with the HTTP response when a change in the cluster occurs.

Failover, Cookies, and HTTP Sessions

When a request contains a session information stored in a cookie, in the POST data, or by URL encoding, the session ID contains a reference to the specific server in which the session was originally established (called the primary server) and a reference to an additional server where the original session is replicated (called the secondary server). A request containing a cookie attempts to connect to the primary server. If that attempt fails, the request is routed to the secondary server. If both the primary and secondary servers fail, the session is lost and the plug-in attempts to make a fresh connection to another server in the dynamic cluster list. For more information see Figure 3-1 Connection Failover.

Note: If the POST data is larger than 64K, the plug-in will not parse the POST data to obtain the session ID. Therefore, if you store the session ID in the POST data, the plug-in cannot route the request to the correct primary or secondary server, resulting in possible loss of session data.

Figure 3-1 Connection Failover

Notes: The HTTP error code thrown by the plug-in depends on the situation. Plug-in will return the HTTP error code 500 in the following conditions:

- Neither WebLogicCluster nor WebLogicPort was specified in the httpd.conf file.

- Unable to resolve the WebLogicHost parameter specified in the httpd.conf file.

- Port number specified by WebLogicPort, in the httpd.conf file, exceeds 65535.

- Unsuccessful in parsing the request while applying the PathTrim property.

- The request header is of type Unknown Transfer-Encoding.

- Failed to read the chunked request.

- Encounetered an error reading POST data from client.

- Failed to open a temporary(temp) file.

- Failed to write POST data to the temp file.

- Encounetered an error reading POST data from the temp file.

- POST timed out.

- SSL was specified without the parameter trustedCAFile.

On the other hand, the HTTP error code 503 is returned when:

- The maximum number of retries is exceeded. This value is computed by dividing ConnectTimeoutSecs by ConnectRetrySecs.

- Idempotent is OFF.