Oct 8, 2009 | Home > Bugzero > FAQs > KB

Application Server - Express, Version 6.1 Operating Systems: AIX, HP-UX, Linux, Solaris, Windows HTTP transport custom properties (from IBM.com) You can use the administrative console to set custom properties for an HTTP transport. The HTTP transport custom properties administrative console page only appears if you have an HTTP transport defined for your system. Important: You can use HTTP transports only on a V5.1 node in a mixed WebSphere Application Server environment. This panel shows if you are using nodes from Version 5.1 and have the script compatibility mode enabled. You must use HTTP transport channels instead of HTTP transports to handle your HTTP requests on all of your other nodes. See HTTP transport channel custom properties for a description of the custom properties that you can specify for an HTTP transport channel. The use of IPv6 (Internet Protocol Version 6) and WS-AT (Web Services Atomic Transactions) are not supported on HTTP transports; they are only supported on HTTP transport channel chains.

If you are using HTTP transports, you can set the following custom properties on either the Web Container or HTTP Transport Custom Properties page on the administrative console. When you set custom properties on the Web container Custom Properties page, all transports inherit the properties. Setting the same properties on a transport overrides similar settings for a Web container. For more information, see the Web container custom properties documentation.

To specify custom properties for a specific transport on the HTTP Transport, complete the following steps through the administrative console unless otherwise indicated:

1. Click Servers > Application Servers > server_name
2. Under Container Settings, expand Web Container Settings and click Web Container.
3. Under Additional Properties, click Web container transport chains.
4. Click the name of the Web transport and then the name of the transport channel for which you want to set the custom property.
5. Click Custom properties > New to add a new custom property.
6. On the settings page, enter the property you want to configure in the Name field and the value you want to set it to in the Value field.
7. Click Apply or OK.
8. Click Save on the console task bar to save your configuration changes.
9. Restart the server.

Following is a list of custom properties provided with the Application Server. These properties are not shown on the settings page for an HTTP transport.

ConnectionIOTimeOut

Use the ConnectionIOTimeOut property to specify how long the J2EE server waits for an I/O operation to complete. Set this variable for each of the HTTP transport definitions on the server. You will need to set this variable for both SSL transport and non-SSL transport. Specifying a value of zero disables the time out function.

Data type	Integer
Default	5 seconds for the i5/OS and distributed platforms

ConnectionKeepAliveTimeout

Use the ConnectionKeepAliveTimeout property to specify the maximum number of seconds to wait for the next request on a keep alive connection.

Data type	Integer
Default	5 seconds for the i5/OS and distributed platforms

MaxConnectBacklog

This property is only valid for i5/OS and distributed platforms. Use the MaxConnectBacklog property to specify the maximum number of outstanding connect requests that the operating system will buffer while it waits for the application server to accept the connections. If a client attempts to connect when this operating system buffer is full, the connect request will be rejected.

Keep in mind that a single client browser might need to open multiple concurrent connections (perhaps 4 or 5); however, also keep in mind that increasing this value consumes more kernel resources. The value of this property is specific to each transport.

Data type	Integer
Default	511

MaxKeepAliveConnections

This property is only valid for i5/OS and distributed platforms. It is ignored on the z/OS platform because asynchronous I/O sockets are used to maintain connections in that environment.Use the MaxKeepAliveConnections property to specify the maximum number of concurrent keep alive (persistent) connections across all HTTP transports. To make a particular transport close connections after a request, you can set MaxKeepAliveConnections to 0 (zero) or you can set KeepAliveEnabled to false on that transport.

The Web server plug-in keeps connections open to the application server as long as it can. However, if the value of this property is too small, performance is negatively impacted because the plug-in has to open a new connection for each request instead of sending multiple requests through one connection. The application server might not accept a new connection under a heavy load if there are too many sockets in TIME_WAIT state. If all client requests are going through the Web server plug-in and there are many TIME_WAIT state sockets for port 9080, the application server is closing connections prematurely, which decreases performance. The application server closes the connection from the plug-in, or from any client, for any of the following reasons:

• The client request was an HTTP 1.0 request when the Web server plug-in always sends HTTP 1.1 requests.
• The maximum number of concurrent keep-alives was reached. A keep-alive must be obtained only once for the life of a connection, that is, after the first request is completed, but before the second request can be read.
• The maximum number of requests for a connection was reached, preventing denial of service attacks in which a client tries to hold on to a keep-alive connection forever.
• A time out occurred while waiting to read the next request or to read the remainder of the current request.

Data type	Integer
Default	90% of the maximum number of threads in the Web container thread pool. This prevents all of the threads from being held by keep alive connections so that there are threads available to handle new incoming connect requests.

MaxKeepAliveRequests

Use the MaxKeepAliveRequests property to specify the maximum number of requests which can be processed on a single keep alive connection. This parameter can help prevent denial of service attacks when a client tries to hold on to a keep-alive connection. The Web server plug-in keeps connections open to the application server as long as it can, providing optimum performance.

On the i5/OS and distributed platforms, when this property is set to 0 (zero), the connection stays open as long as the application server is running.

Data type	Integer
Default	100 requests for the i5/OS and distributed platforms

KeepAliveEnabled

This property is only valid for i5/OS and distributed platforms. Use the KeepAliveEnabled property to specify whether or not to keep connections alive

Data type	String
Value	true or false
Default	true

RemoveServerHeader

Use this property to specify whether an existing server header is removed before a response message is sent. If this property is set to true, the value specified for the ServerHeaderValue property is ignored.

Data type	String
Value	true or false
Default	false

Attention: This custom property takes effect on the Web container level only. You cannot set it on the transport level. To set this custom property, see Modifying the default Web container configuration.

ResponseBufferSize

This property is used to specify, in bytes, the default size of the initial buffer allocation for the response buffer. When the buffer fills up, a flush for this buffer space will automatically occur. If a value is not specified for this property, the default response buffer size of 32K bytes is used.

The setBufferSize() API method can be used to override the value specified for this custom property at the individual servlet level.

Data type	Integer
Default	32000 bytes

ServerHeaderValue

Use this property to specify a server header this is added to outgoing response messages if server header is not already provided. This property is ignored if the RemoveServerHeader property is set to true.

Data type	string
Default	WebSphere Application Server/x.x x.x is the version of WebSphere Application Server that you are using.

Attention: This custom property takes effect on the Web container level only. You cannot set it on the transport level. To set this custom property, see Modifying the default Web container configuration.

SoLingerValue

Use this property to specify, in seconds, the amount, that the socket close operation waits for data contained in the TCP/IP send buffer to be sent. This property is ignored if the UseSoLinger property is set to false.

Data type	Integer
Default	20 seconds

TcpNoDelay

Use this property to set the socket TCP_NODELAY option which enables and disables the use of the TCP Nagle algorithm for connections received on this transport. When this property is set to true, use of the Nagle algorithm is disabled.

Data type	String
Value	true or false
Default	true

Trusted

Use the Trusted property to indicate that the application server can use the private headers that the Web server plug-in adds to requests.

Data type	String
Value	true or false
Default	false

Important: This property must be set to false for Secure Sockets Layer (SSL) client certificate authentication to work.

UseSoLinger

Use this property to set the socket SO_LINGER option. This property configures whether the socket close operation waits until all of the data contained in the TCP/IP send buffer is sent before closing a connection. If this property is set to true, and the time expires before the all of the content of the send buffer sent, any data remaining in the send buffer is lost.

The SoLingerValue property is ignored if this property is set to false.

Data type	String
Value	true or false
Default	true