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<!DOCTYPE document [
  <!ENTITY project SYSTEM "project.xml">
]>
<document url="ajp.html">

  &project;

  <properties>
    <author email="remm@apache.org">Remy Maucherat</author>
    <author email="yoavs@apache.org">Yoav Shapira</author>
    <author email="arjaquith@mindspring.com">Andrew R. Jaquith</author>
    <title>The AJP Connector</title>
  </properties>

<body>

<section name="Table of Contents">
<toc/>
</section>

<section name="Introduction">

  <p>The <strong>AJP Connector</strong> element represents a
  <strong>Connector</strong> component that communicates with a web
  connector via the <code>AJP</code> protocol.  This is used for cases
  where you wish to invisibly integrate Tomcat 6 into an existing (or new)
  Apache installation, and you want Apache to handle the static content
  contained in the web application, and/or utilize Apache's SSL
  processing.</p>

  <p>This connector supports load balancing when used in conjunction with
  the <code>jvmRoute</code> attribute of the 
  <a href="engine.html">Engine</a>.</p>

<p>The native connectors supported with this Tomcat release are:
<ul>
  <li>JK 1.2.x with any of the supported servers</li>
  <li>mod_proxy on Apache httpd 2.x (included by default in Apache HTTP Server 2.2), 
      with AJP enabled: see
      <a href="http://httpd.apache.org/docs/2.2/mod/mod_proxy_ajp.html">the httpd docs</a>
      for details.</li>
</ul>
</p>

<p><b>Other native connectors supporting AJP may work, but are no longer supported.</b></p>

</section>


<section name="Attributes">

  <subsection name="Common Attributes">

  <p>All implementations of <strong>Connector</strong>
  support the following attributes:</p>

  <attributes>

    <attribute name="allowTrace" required="false">
      <p>A boolean value which can be used to enable or disable the TRACE
      HTTP method. If not specified, this attribute is set to false.</p>
    </attribute>

    <attribute name="emptySessionPath" required="false">
      <p>If set to <code>true</code>, all paths for session cookies will be set
      to <code>/</code>. This can be useful for portlet specification implementations.
      If not specified, this attribute is set to <code>false</code>.</p>
    </attribute>

    <attribute name="enableLookups" required="false">
      <p>Set to <code>true</code> if you want calls to
      <code>request.getRemoteHost()</code> to perform DNS lookups in
      order to return the actual host name of the remote client.  Set
      to <code>false</code> to skip the DNS lookup and return the IP
      address in String form instead (thereby improving performance).
      By default, DNS lookups are disabled.</p>
    </attribute>

    <attribute name="maxHeaderCount" required="false">
      <p>The maximum number of headers in a request that are allowed by the
      container. A request that contains more headers than the specified limit
      will be rejected. A value of less than 0 means no limit.
      If not specified, a default of 100 is used.</p>
    </attribute>

    <attribute name="maxParameterCount" required="false">
      <p>The maximum number of parameters (GET plus POST) which will be
      automatically parsed by the container. A value of less than 0 means no
      limit. If not specified, a default of 10000 is used. Note that
      <code>FailedRequestFilter</code> <a href="filter.html">filter</a> can be
      used to reject requests that hit the limit.</p>
    </attribute>

    <attribute name="maxPostSize" required="false">
      <p>The maximum size in bytes of the POST which will be handled by
      the container FORM URL parameter parsing. The feature can be disabled by
      setting this attribute to a value less than or equal to 0.
      If not specified, this attribute is set to 2097152 (2 megabytes).</p>
    </attribute>

    <attribute name="maxSavePostSize" required="false">
      <p>The maximum size in bytes of the POST which will be saved/buffered by
      the container during FORM or CLIENT-CERT authentication. For both types
      of authentication, the POST will be saved/buffered before the user is
      authenticated. For CLIENT-CERT authentication, the POST is buffered for
      the duration of the SSL handshake and the buffer emptied when the request
      is processed. For FORM authentication the POST is saved whilst the user
      is re-directed to the login form and is retained until the user
      successfully authenticates or the session associated with the
      authentication request expires. The limit can be disabled by setting this
      attribute to -1. Setting the attribute to zero will disable the saving of
      POST data during authentication. If not specified, this attribute is set
      to 4096 (4 kilobytes).</p>
    </attribute>

    <attribute name="parseBodyMethods" required="false">
      <p>A comma-separated list of HTTP methods for which request
      bodies will be parsed for request parameters identically
      to POST. This is useful in RESTful applications that want to
      support POST-style semantics for PUT requests.
      Note that any setting other than <code>POST</code> causes Tomcat
      to behave in a way that does against the intent of the servlet
      specification.
      The HTTP method TRACE is specifically forbidden here in accordance
      with the HTTP specification.
      The default is <code>POST</code></p>
    </attribute>

    <attribute name="port" required="true">
      <p>The TCP port number on which this <strong>Connector</strong>
      will create a server socket and await incoming connections.  Your
      operating system will allow only one server application to listen
      to a particular port number on a particular IP address.</p>
    </attribute>

    <attribute name="protocol" required="false">
      <p>Sets the protocol to handle incoming traffic. The default value is
        <code>AJP/1.3</code> and configures
        <code>org.apache.jk.server.JkCoyoteHandler</code> the original blocking
        Java connector by default.<br/>
        If the <code>PATH</code> (Windows) or <code>LD_LIBRARY_PATH</code>
        (on most unix systems) environment variables contain the Tomcat
        native library, the native/APR connector will automatically be
        configured instead.<br/>
        To use an explicit protocol rather than rely on the auto-switching
        mechanism described above, the following values may be used:<br/>
        <code>org.apache.jk.server.JkCoyoteHandler</code>
        - original blocking Java connector<br/>
        <code>org.apache.coyote.ajp.AjpProtocol</code>
        - new blocking Java connector that supports an executor<br/>
        <code>org.apache.coyote.ajp.AjpAprProtocol</code>
        - the APR/native connector.<br/>
      Custom implementations may also be used.</p>
    </attribute>

    <attribute name="proxyName" required="false">
      <p>If this <strong>Connector</strong> is being used in a proxy
      configuration, configure this attribute to specify the server name
      to be returned for calls to <code>request.getServerName()</code>.
      See <a href="#Proxy Support">Proxy Support</a> for more
      information.</p>
    </attribute>

    <attribute name="proxyPort" required="false">
      <p>If this <strong>Connector</strong> is being used in a proxy
      configuration, configure this attribute to specify the server port
      to be returned for calls to <code>request.getServerPort()</code>.
      See <a href="#Proxy Support">Proxy Support</a> for more
      information.</p>
    </attribute>

    <attribute name="redirectPort" required="false">
      <p>If this <strong>Connector</strong> is supporting non-SSL
      requests, and a request is received for which a matching
      <code>&lt;security-constraint&gt;</code> requires SSL transport,
      Catalina will automatically redirect the request to the port
      number specified here.</p>
    </attribute>

    <attribute name="request.registerRequests" required="false">
      <p>This attribute controls request registration for JMX monitoring
      of the Connector.  It is enabled by default, but may be turned
      it off to save a bit of memory.</p>
    </attribute>

    <attribute name="scheme" required="false">
      <p>Set this attribute to the name of the protocol you wish to have
      returned by calls to <code>request.getScheme()</code>.  For
      example, you would set this attribute to "<code>https</code>"
      for an SSL Connector.  The default value is "<code>http</code>".
      See <a href="#SSL Support">SSL Support</a> for more information.</p>
    </attribute>

    <attribute name="secure" required="false">
      <p>Set this attribute to <code>true</code> if you wish to have
      calls to <code>request.isSecure()</code> to return <code>true</code>
      for requests received by this Connector (you would want this on an
      SSL Connector).  The default value is <code>false</code>.</p>
    </attribute>

    <attribute name="URIEncoding" required="false">
      <p>This specifies the character encoding used to decode the URI bytes,
      after %xx decoding the URL. If not specified, ISO-8859-1 will be used.
      </p>
    </attribute>

    <attribute name="useBodyEncodingForURI" required="false">
      <p>This specifies if the encoding specified in contentType should be used
      for URI query parameters, instead of using the URIEncoding. This
      setting is present for compatibility with Tomcat 4.1.x, where the
      encoding specified in the contentType, or explicitly set using
      Request.setCharacterEncoding method was also used for the parameters from
      the URL. The default value is <code>false</code>.
      </p>
    </attribute>

    <attribute name="useIPVHosts" required="false">
      <p>Set this attribute to <code>true</code> to cause Tomcat to use
      the ServerName passed by the native web server to determine the Host
      to send the request to.  The default value is <code>false</code>.</p>
    </attribute>

    <attribute name="xpoweredBy" required="false">
      <p>Set this attribute to <code>true</code> to cause Tomcat to advertise
      support for the Servlet specification using the header recommended in the
      specification.  The default value is <code>false</code>.</p>
    </attribute>
    
    

  </attributes>

  </subsection>

  <subsection name="Standard Implementations">

  <p>To use AJP, you
  must specify the protocol attribute (see above).</p>

  <p><strong>These implementations support the AJP 1.3 protocol.</strong></p>

  <p>They support the following additional attributes (in addition to the
  common attributes listed above):</p>

  <attributes>

    <attribute name="address" required="false">
      <p>For servers with more than one IP address, this attribute
      specifies which address will be used for listening on the specified
      port.  By default, this port will be used on all IP addresses
      associated with the server. A value of <code>127.0.0.1</code>
      indicates that the Connector will only listen on the loopback
      interface.</p>
    </attribute>

    <attribute name="backlog" required="false">
      <p>The maximum queue length for incoming connection requests when
      all possible request processing threads are in use.  Any requests
      received when the queue is full will be refused.  The default
      value is 100.</p>
    </attribute>

    <attribute name="bufferSize" required="false">
      <p>The size of the output buffer to use.  If less than or equal to zero,
         then output buffering is disabled.  The default value is -1
         (i.e. buffering disabled)</p>
    </attribute>

    <attribute name="clientCertProvider" required="false">
      <p>When client certificate information is presented in a form other than
      instances of <code>java.security.cert.X509Certificate</code> it needs to
      be converted before it can be used and this property controls which JSSE
      provider is used to perform the conversion. For example it is used with
      the AJP connectors, the <a href="http.html">HTTP APR connector</a> and
      with the <a href="valve.html#SSL_Authenticator_Valve">
      org.apache.catalina.valves.SSLValve</a>.If not specified, the default
      provider will be used.</p>
    </attribute>

    <attribute name="connectionTimeout" required="false">
      <p>The number of milliseconds this <strong>Connector</strong> will wait,
      after accepting a connection, for the request URI line to be
      presented.  The default value is infinite (i.e. no timeout).</p>
    </attribute>
    
    <attribute name="deferAccept" required="false">
      <p>Sets the <code>TCP_DEFER_ACCEPT</code> flag on the listening socket for
      this connector. The default value is <code>true</code> where
      <code>TCP_DEFER_ACCEPT</code> is supported by the operating system,
      otherwise it is <code>false</code>.</p>
    </attribute>
    
    <attribute name="executor" required="false">
      <p>A reference to the name in an <a href="executor.html">Executor</a> element.
         If this attribute is enabled, and the named executor exists, the connector will
         use the executor, and all the other thread attributes will be ignored.
         This attribute is not supported by the original blocking Java
         connector.</p>
    </attribute>

    <attribute name="keepAliveTimeout" required="false">
      <p>The number of milliseconds this <strong>Connector</strong> will wait for
       another AJP request before closing the connection.
       The default value is to use the value that has been set for the
       connectionTimeout attribute.</p>
    </attribute>

    <attribute name="maxThreads" required="false">
      <p>The maximum number of request processing threads to be created
      by this <strong>Connector</strong>, which therefore determines the
      maximum number of simultaneous requests that can be handled.  If
      not specified, this attribute is set to 200. If an executor is associated
      with this connector, this attribute is ignored as the connector will 
      execute tasks using the executor rather than an internal thread pool.</p>
    </attribute>

    <attribute name="packetSize" required="false">
      <p>This attribute sets the maximum AJP packet size in Bytes. The maximum
      value is 65536. It should be the same as the <code>max_packet_size</code>
      directive configured for mod_jk. Normally it is not necessary to change
      the maximum packet size. Problems with the default value have been
      reported when sending certificates or certificate chains. The default
      value is 8192.</p>
    </attribute>

    <attribute name="port" required="true">
      <p>The TCP port number on which this <strong>Connector</strong>
      will create a server socket and await incoming connections.  Your
      operating system will allow only one server application to listen
      to a particular port number on a particular IP address.</p>
    </attribute>

    <attribute name="request.secret" required="false">
      <p>Only requests from workers with this secret keyword will be accepted.
      </p>
    </attribute>

    <attribute name="request.shutdownEnabled" required="false">
      <p>If true and a secret has been configured, a correctly formatted AJP
      request (that includes the secret) will shutdown the Tomcat instance
      associated with this connector. This is set to <code>false</code> by
      default.</p>
    </attribute>

    <attribute name="request.useSecret" required="false">
      <p>If set to <code>true</code>, then a random value for
      <code>request.secret</code> will be generated. It is for use with
      <code>request.shutdownEnabled</code>. This is set to <code>false</code>
      by default.</p>
    </attribute>

    <attribute name="tcpNoDelay" required="false">
      <p>If set to <code>true</code>, the TCP_NO_DELAY option will be
      set on the server socket, which improves performance under most
      circumstances.  This is set to <code>true</code> by default.</p>
    </attribute>

    <attribute name="tomcatAuthentication" required="false">
      <p>If set to <code>true</code>, the authentication will be done in Tomcat. 
      Otherwise, the authenticated principal will be propagated from the native
      webserver and used for authorization in Tomcat.  
      The default value is <code>true</code>.</p>
    </attribute>

  </attributes>

  </subsection>

</section>


<section name="Nested Components">

  <p>None at this time.</p>

</section>


</body>

</document>
