Google Git
Sign in
apache / tomcat / trunk / . / webapps / docs / config / http.xml
blob: 782c1ddadd0ec94dff8858ae9790f44ed1179a24 [file] [log] [blame]
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!DOCTYPE document [
<!ENTITY project SYSTEM "project.xml">
]>
<document url="http.html">
&project;
<properties>
<author email="craigmcc@apache.org">Craig R. McClanahan</author>
<author email="yoavs@apache.org">Yoav Shapira</author>
<title>The HTTP Connector</title>
</properties>
<body>
<section name="Table of Contents">
<toc/>
</section>
<section name="Introduction">
<p>The <strong>HTTP Connector</strong> element represents a
<strong>Connector</strong> component that supports the HTTP/1.1 protocol.
It enables Catalina to function as a stand-alone web server, in addition
to its ability to execute servlets and JSP pages. A particular instance
of this component listens for connections on a specific TCP port number
on the server. One or more such <strong>Connectors</strong> can be
configured as part of a single <a href="service.html">Service</a>, each
forwarding to the associated <a href="engine.html">Engine</a> to perform
request processing and create the response.</p>
<p>If you wish to configure the <strong>Connector</strong> that is used
for connections to web servers using the AJP protocol (such as the
<code>mod_jk 1.2.x</code> connector for Apache 1.3), please refer to the
<a href="ajp.html">AJP Connector</a> documentation.</p>
<p>Each incoming request requires
a thread for the duration of that request. If more simultaneous requests
are received than can be handled by the currently available request
processing threads, additional threads will be created up to the
configured maximum (the value of the <code>maxThreads</code> attribute).
If still more simultaneous requests are received, they are stacked up
inside the server socket created by the <strong>Connector</strong>, up to
the configured maximum (the value of the <code>acceptCount</code>
attribute). Any further simultaneous requests will receive "connection
refused" errors, until resources are available to process them.</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="asyncTimeout" required="false">
<p>The default timeout for asynchronous requests in milliseconds. If not
specified, this attribute is set to the Servlet specification default of
30000 (30 seconds).</p>
</attribute>
<attribute name="defaultSSLHostConfigName" required="false">
<p>The name of the default <strong>SSLHostConfig</strong> that will be
used for secure connections (if this connector is configured for secure
connections) if the client connection does not provide SNI or if the SNI
is provided but does not match any configured
<strong>SSLHostConfig</strong>. If not specified the default value of
<code>_default_</code> will be used.</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 parameter and value pairs (GET plus POST) which
will be automatically parsed by the container. Parameter and value pairs
beyond this limit will be ignored. 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 limit can be disabled by
setting this attribute to a value less than zero. If not specified, this
attribute is set to 2097152 (2 megabytes). Note that the
<a href="filter.html#Failed_Request_Filter"><code>FailedRequestFilter</code></a>
can be used to reject requests that exceed this limit.</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 using <code>application/x-www-form-urlencoded</code> 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 goes 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. If the special
value of 0 (zero) is used, then Tomcat will select a free port at random
to use for this connector. This is typically only useful in embedded and
testing applications.</p>
</attribute>
<attribute name="protocol" required="false">
<p>Sets the protocol to handle incoming traffic. The default value is
<code>HTTP/1.1</code> which uses an auto-switching mechanism to select
either a Java NIO based connector or an APR/native based connector.
If the <code>PATH</code> (Windows) or <code>LD_LIBRARY_PATH</code> (on
most unix systems) environment variables contain the Tomcat native
library, and the <code>AprLifecycleListener</code> that is used to
initialize APR has its <code>useAprConnector</code> attribute set to
<code>true</code>, the APR/native connector will be used. If the native library
cannot be found or the attribute is not configured, the Java NIO based
connector will be used. Note that the APR/native connector has different
settings for HTTPS than the Java connectors.<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.coyote.http11.Http11NioProtocol</code> -
non blocking Java NIO connector<br/>
<code>org.apache.coyote.http11.Http11Nio2Protocol</code> -
non blocking Java NIO2 connector<br/>
<code>org.apache.coyote.http11.Http11AprProtocol</code> -
the APR/native connector.<br/>
Custom implementations may also be used.<br/>
Take a look at our <a href="#Connector_Comparison">Connector
Comparison</a> chart. The configuration for both Java connectors is
identical, for http and https.<br/>
For more information on the APR connector and APR specific SSL settings
please visit the <a href="../apr.html">APR documentation</a>
</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="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>".
</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 or a non SSL connector that is receiving data from a
SSL accelerator, like a crypto card, a SSL appliance or even a webserver.
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, UTF-8 will be used unless
the <code>org.apache.catalina.STRICT_SERVLET_COMPLIANCE</code>
<a href="systemprops.html">system property</a> is set to <code>true</code>
in which case 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>
<p><strong>Notes:</strong> 1) This setting is applied only to the
query string of a request. Unlike <code>URIEncoding</code> it does not
affect the path portion of a request URI. 2) If request character
encoding is not known (is not provided by a browser and is not set by
<code>SetCharacterEncodingFilter</code> or a similar filter using
Request.setCharacterEncoding method), the default encoding is always
"ISO-8859-1". The <code>URIEncoding</code> setting has no effect on
this default.
</p>
</attribute>
<attribute name="useIPVHosts" required="false">
<p>Set this attribute to <code>true</code> to cause Tomcat to use
the IP address that the request was received on 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 Implementation">
<p>The standard HTTP connectors (NIO, NIO2 and APR/native) all support the
following attributes in addition to the common Connector attributes listed
above.</p>
<attributes>
<attribute name="acceptCount" 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="acceptorThreadCount" required="false">
<p>The number of threads to be used to accept connections. Increase this
value on a multi CPU machine, although you would never really need more
than <code>2</code>. Also, with a lot of non keep alive connections, you
might want to increase this value as well. Default value is
<code>1</code>.</p>
</attribute>
<attribute name="acceptorThreadPriority" required="false">
<p>The priority of the acceptor threads. The threads used to accept
new connections. The default value is <code>5</code> (the value of the
<code>java.lang.Thread.NORM_PRIORITY</code> constant). See the JavaDoc
for the <code>java.lang.Thread</code> class for more details on what
this priority means.</p>
</attribute>
<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, the connector will listen all local addresses. Unless the JVM is
configured otherwise using system properties, the Java based connectors
(NIO, NIO2) will listen on both IPv4 and IPv6 addresses when configured
with either <code>0.0.0.0</code> or <code>::</code>. The APR/native
connector will only listen on IPv4 addresses if configured with
<code>0.0.0.0</code> and will listen on IPv6 addresses (and optionally
IPv4 addresses depending on the setting of <strong>ipv6onlyv6</strong>) if
configured with <code>::</code>.</p>
</attribute>
<attribute name="allowHostHeaderMismatch" required="false">
<p>By default Tomcat will reject requests that specify a host in the
request line but specify a different host in the host header. This
check can be disabled by setting this attribute to <code>true</code>. If
not specified, the default is <code>false</code>.</p>
</attribute>
<attribute name="allowedTrailerHeaders" required="false">
<p>By default Tomcat will ignore all trailer headers when processing
chunked input. For a header to be processed, it must be added to this
comma-separated list of header names.</p>
</attribute>
<attribute name="bindOnInit" required="false">
<p>Controls when the socket used by the connector is bound. By default it
is bound when the connector is initiated and unbound when the connector is
destroyed. If set to <code>false</code>, the socket will be bound when the
connector is started and unbound when it is stopped.</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 <a href="ajp.html">AJP connectors</a>, the HTTP APR connector 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="compressibleMimeType" required="false">
<p>The value is a comma separated list of MIME types for which HTTP
compression may be used.
The default value is
<code>
text/html,text/xml,text/plain,text/css,text/javascript,application/javascript,application/json,application/xml
</code>.
</p>
</attribute>
<attribute name="compression" required="false">
<p>The <strong>Connector</strong> may use HTTP/1.1 GZIP compression in
an attempt to save server bandwidth. The acceptable values for the
parameter is "off" (disable compression), "on" (allow compression, which
causes text data to be compressed), "force" (forces compression in all
cases), or a numerical integer value (which is equivalent to "on", but
specifies the minimum amount of data before the output is compressed). If
the content-length is not known and compression is set to "on" or more
aggressive, the output will also be compressed. If not specified, this
attribute is set to "off".</p>
<p><em>Note</em>: There is a tradeoff between using compression (saving
your bandwidth) and using the sendfile feature (saving your CPU cycles).
If the connector supports the sendfile feature, e.g. the NIO connector,
using sendfile will take precedence over compression. The symptoms will
be that static files greater that 48 Kb will be sent uncompressed.
You can turn off sendfile by setting <code>useSendfile</code> attribute
of the connector, as documented below, or change the sendfile usage
threshold in the configuration of the
<a href="../default-servlet.html">DefaultServlet</a> in the default
<code>conf/web.xml</code> or in the <code>web.xml</code> of your web
application.
</p>
</attribute>
<attribute name="compressionMinSize" required="false">
<p>If <strong>compression</strong> is set to "on" then this attribute
may be used to specify the minimum amount of data before the output is
compressed. If not specified, this attribute is defaults to "2048".</p>
</attribute>
<attribute name="connectionLinger" required="false">
<p>The number of seconds during which the sockets used by this
<strong>Connector</strong> will linger when they are closed. The default
value is <code>-1</code> which disables socket linger.</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. Use a value of -1 to indicate no (i.e. infinite) timeout.
The default value is 60000 (i.e. 60 seconds) but note that the standard
server.xml that ships with Tomcat sets this to 20000 (i.e. 20 seconds).
Unless <strong>disableUploadTimeout</strong> is set to <code>false</code>,
this timeout will also be used when reading the request body (if any).</p>
</attribute>
<attribute name="connectionUploadTimeout" required="false">
<p>Specifies the timeout, in milliseconds, to use while a data upload is
in progress. This only takes effect if
<strong>disableUploadTimeout</strong> is set to <code>false</code>.
</p>
</attribute>
<attribute name="disableUploadTimeout" required="false">
<p>This flag allows the servlet container to use a different, usually
longer connection timeout during data upload. If not specified, this
attribute is set to <code>true</code> which disables this longer timeout.
</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 set, and the named executor exists, the
connector will use the executor, and all the other thread attributes will
be ignored. Note that if a shared executor is not specified for a
connector then the connector will use a private, internal executor to
provide the thread pool.</p>
</attribute>
<attribute name="executorTerminationTimeoutMillis" required="false">
<p>The time that the private internal executor will wait for request
processing threads to terminate before continuing with the process of
stopping the connector. If not set, the default is <code>5000</code> (5
seconds).</p>
</attribute>
<attribute name="keepAliveTimeout" required="false">
<p>The number of milliseconds this <strong>Connector</strong> will wait
for another HTTP request before closing the connection. The default value
is to use the value that has been set for the
<strong>connectionTimeout</strong> attribute.
Use a value of -1 to indicate no (i.e. infinite) timeout.</p>
</attribute>
<attribute name="maxConnections" required="false">
<p>The maximum number of connections that the server will accept and
process at any given time. When this number has been reached, the server
will accept, but not process, one further connection. This additional
connection be blocked until the number of connections being processed
falls below <strong>maxConnections</strong> at which point the server will
start accepting and processing new connections again. Note that once the
limit has been reached, the operating system may still accept connections
based on the <code>acceptCount</code> setting. The default value varies by
connector type. For NIO and NIO2 the default is <code>10000</code>.
For APR/native, the default is <code>8192</code>.</p>
<p>Note that for APR/native on Windows, the configured value will be
reduced to the highest multiple of 1024 that is less than or equal to
maxConnections. This is done for performance reasons.<br/>
If set to a value of -1, the maxConnections feature is disabled
and connections are not counted.</p>
</attribute>
<attribute name="maxCookieCount" required="false">
<p>The maximum number of cookies that are permitted for a request. A value
of less than zero means no limit. If not specified, a default value of 200
will be used.</p>
</attribute>
<attribute name="maxExtensionSize" required="false">
<p>Limits the total length of chunk extensions in chunked HTTP requests.
If the value is <code>-1</code>, no limit will be imposed. If not
specified, the default value of <code>8192</code> will be used.</p>
</attribute>
<attribute name="maxHttpHeaderSize" required="false">
<p>The maximum size of the request and response HTTP header, specified
in bytes. If not specified, this attribute is set to 8192 (8 KB).</p>
</attribute>
<attribute name="maxKeepAliveRequests" required="false">
<p>The maximum number of HTTP requests which can be pipelined until
the connection is closed by the server. Setting this attribute to 1 will
disable HTTP/1.0 keep-alive, as well as HTTP/1.1 keep-alive and
pipelining. Setting this to -1 will allow an unlimited amount of
pipelined or keep-alive HTTP requests.
If not specified, this attribute is set to 100.</p>
</attribute>
<attribute name="maxSwallowSize" required="false">
<p>The maximum number of request body bytes (excluding transfer encoding
overhead) that will be swallowed by Tomcat for an aborted upload. An
aborted upload is when Tomcat knows that the request body is going to be
ignored but the client still sends it. If Tomcat does not swallow the body
the client is unlikely to see the response. If not specified the default
of 2097152 (2 megabytes) will be used. A value of less than zero indicates
that no limit should be enforced.</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. Note
that if an executor is configured any value set for this attribute will be
recorded correctly but it will be reported (e.g. via JMX) as
<code>-1</code> to make clear that it is not used.</p>
</attribute>
<attribute name="maxTrailerSize" required="false">
<p>Limits the total length of trailing headers in the last chunk of
a chunked HTTP request. If the value is <code>-1</code>, no limit will be
imposed. If not specified, the default value of <code>8192</code> will be
used.</p>
</attribute>
<attribute name="minSpareThreads" required="false">
<p>The minimum number of threads always kept running. This includes both
active and idle threads. If not specified, the default of <code>10</code>
is used. 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. Note that if an executor is configured any
value set for this attribute will be recorded correctly but it will be
reported (e.g. via JMX) as <code>-1</code> to make clear that it is not
used.</p>
</attribute>
<attribute name="noCompressionUserAgents" required="false">
<p>The value is a regular expression (using <code>java.util.regex</code>)
matching the <code>user-agent</code> header of HTTP clients for which
compression should not be used,
because these clients, although they do advertise support for the
feature, have a broken implementation.
The default value is an empty String (regexp matching disabled).</p>
</attribute>
<attribute name="processorCache" required="false">
<p>The protocol handler caches Processor objects to speed up performance.
This setting dictates how many of these objects get cached.
<code>-1</code> means unlimited, default is <code>200</code>. If not using
Servlet 3.0 asynchronous processing, a good default is to use the same as
the maxThreads setting. If using Servlet 3.0 asynchronous processing, a
good default is to use the larger of maxThreads and the maximum number of
expected concurrent requests (synchronous and asynchronous).</p>
</attribute>
<attribute name="rejectIllegalHeaderName" required="false">
<p>If an HTTP request is received that contains an illegal header name
(i.e. the header name is not a token) this setting determines if the
request will be rejected with a 400 response (<code>true</code>) or if the
illegal header be ignored (<code>false</code>). The default value is
<code>true</code> which will cause the request to be rejected.</p>
</attribute>
<attribute name="relaxedPathChars" required="false">
<p>The <a href="https://tools.ietf.org/rfc/rfc7230.txt">HTTP/1.1
specification</a> requires that certain characters are %nn encoded when
used in URI paths. Unfortunately, many user agents including all the major
browsers are not compliant with this specification and use these
characters in unencoded form. To prevent Tomcat rejecting such requests,
this attribute may be used to specify the additional characters to allow.
If not specified, no additional characters will be allowed. The value may
be any combination of the following characters:
<code>&quot; &lt; &gt; [ \ ] ^ ` { | }</code> . Any other characters
present in the value will be ignored.</p>
</attribute>
<attribute name="relaxedQueryChars" required="false">
<p>The <a href="https://tools.ietf.org/rfc/rfc7230.txt">HTTP/1.1
specification</a> requires that certain characters are %nn encoded when
used in URI query strings. Unfortunately, many user agents including all
the major browsers are not compliant with this specification and use these
characters in unencoded form. To prevent Tomcat rejecting such requests,
this attribute may be used to specify the additional characters to allow.
If not specified, no additional characters will be allowed. The value may
be any combination of the following characters:
<code>&quot; &lt; &gt; [ \ ] ^ ` { | }</code> . Any other characters
present in the value will be ignored.</p>
</attribute>
<attribute name="restrictedUserAgents" required="false">
<p>The value is a regular expression (using <code>java.util.regex</code>)
matching the <code>user-agent</code> header of HTTP clients for which
HTTP/1.1 or HTTP/1.0 keep alive should not be used, even if the clients
advertise support for these features.
The default value is an empty String (regexp matching disabled).</p>
</attribute>
<attribute name="server" required="false">
<p>Overrides the Server header for the http response. If set, the value
for this attribute overrides any Server header set by a web application.
If not set, any value specified by the application is used. If the
application does not specify a value then no Server header is set.</p>
</attribute>
<attribute name="serverRemoveAppProvidedValues" required="false">
<p>If <code>true</code>, any Server header set by a web
application will be removed. Note that if <strong>server</strong> is set,
this attribute is effectively ignored. If not set, the default value of
<code>false</code> will be used.</p>
</attribute>
<attribute name="SSLEnabled" required="false">
<p>Use this attribute to enable SSL traffic on a connector.
To turn on SSL handshake/encryption/decryption on a connector
set this value to <code>true</code>.
The default value is <code>false</code>.
When turning this value <code>true</code> you will want to set the
<code>scheme</code> and the <code>secure</code> attributes as well
to pass the correct <code>request.getScheme()</code> and
<code>request.isSecure()</code> values to the servlets
See <a href="#SSL_Support">SSL Support</a> for more information.
</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="threadPriority" required="false">
<p>The priority of the request processing threads within the JVM.
The default value is <code>5</code> (the value of the
<code>java.lang.Thread.NORM_PRIORITY</code> constant). See the JavaDoc
for the <code>java.lang.Thread</code> class for more details on what
this priority means. 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. Note
that if an executor is configured any value set for this attribute will be
recorded correctly but it will be reported (e.g. via JMX) as
<code>-1</code> to make clear that it is not used.</p>
</attribute>
<attribute name="throwOnFailure" required="false">
<p>If the Connector experiences an Exception during a Lifecycle transition
should the Exception be rethrown or logged? If not specified, the default
of <code>false</code> will be used. Note that the default can be changed
by the <code>org.apache.catalina.startup.EXIT_ON_INIT_FAILURE</code>
system property.</p>
</attribute>
</attributes>
</subsection>
<subsection name="Java TCP socket attributes">
<p>The NIO and NIO2 implementation support the following Java TCP
socket attributes in addition to the common Connector and HTTP attributes
listed above.</p>
<attributes>
<attribute name="socket.rxBufSize" required="false">
<p>(int)The socket receive buffer (SO_RCVBUF) size in bytes. JVM default
used if not set.</p>
</attribute>
<attribute name="socket.txBufSize" required="false">
<p>(int)The socket send buffer (SO_SNDBUF) size in bytes. JVM default
used if not set.</p>
</attribute>
<attribute name="socket.tcpNoDelay" required="false">
<p>(bool)This is equivalent to standard attribute
<strong>tcpNoDelay</strong>.</p>
</attribute>
<attribute name="socket.soKeepAlive" required="false">
<p>(bool)Boolean value for the socket's keep alive setting
(SO_KEEPALIVE). JVM default used if not set.</p>
</attribute>
<attribute name="socket.ooBInline" required="false">
<p>(bool)Boolean value for the socket OOBINLINE setting. JVM default
used if not set.</p>
</attribute>
<attribute name="socket.soReuseAddress" required="false">
<p>(bool)Boolean value for the sockets reuse address option
(SO_REUSEADDR). JVM default used if not set.</p>
</attribute>
<attribute name="socket.soLingerOn" required="false">
<p>(bool)Boolean value for the sockets so linger option (SO_LINGER).
A value for the standard attribute <strong>connectionLinger</strong>
that is &gt;=0 is equivalent to setting this to <code>true</code>.
A value for the standard attribute <strong>connectionLinger</strong>
that is &lt;0 is equivalent to setting this to <code>false</code>.
Both this attribute and <code>soLingerTime</code> must be set else the
JVM defaults will be used for both.</p>
</attribute>
<attribute name="socket.soLingerTime" required="false">
<p>(int)Value in seconds for the sockets so linger option (SO_LINGER).
This is equivalent to standard attribute
<strong>connectionLinger</strong>.
Both this attribute and <code>soLingerOn</code> must be set else the
JVM defaults will be used for both.</p>
</attribute>
<attribute name="socket.soTimeout" required="false">
<p>This is equivalent to standard attribute
<strong>connectionTimeout</strong>.</p>
</attribute>
<attribute name="socket.performanceConnectionTime" required="false">
<p>(int)The first value for the performance settings. See
<a href="http://docs.oracle.com/javase/7/docs/api/java/net/Socket.html#setPerformancePreferences(int,%20int,%20int)">Socket Performance Options</a>.
All three performance attributes must be set else the JVM defaults will
be used for all three.</p>
</attribute>
<attribute name="socket.performanceLatency" required="false">
<p>(int)The second value for the performance settings. See
<a href="http://docs.oracle.com/javase/7/docs/api/java/net/Socket.html#setPerformancePreferences(int,%20int,%20int)">Socket Performance Options</a>.
All three performance attributes must be set else the JVM defaults will
be used for all three.</p>
</attribute>
<attribute name="socket.performanceBandwidth" required="false">
<p>(int)The third value for the performance settings. See
<a href="http://docs.oracle.com/javase/7/docs/api/java/net/Socket.html#setPerformancePreferences(int,%20int,%20int)">Socket Performance Options</a>.
All three performance attributes must be set else the JVM defaults will
be used for all three.</p>
</attribute>
<attribute name="socket.unlockTimeout" required="false">
<p>(int) The timeout for a socket unlock. When a connector is stopped, it will try to release the acceptor thread by opening a connector to itself.
The default value is <code>250</code> and the value is in milliseconds</p>
</attribute>
</attributes>
</subsection>
<subsection name="NIO specific configuration">
<p>The following attributes are specific to the NIO connector.</p>
<attributes>
<attribute name="pollerThreadCount" required="false">
<p>(int)The number of threads to be used to run for the polling events.
Default value is <code>1</code> per processor but not more than 2.<br/>
When accepting a socket, the operating system holds a global lock. So the benefit of
going above 2 threads diminishes rapidly. Having more than one thread is for
system that need to accept connections very rapidly. However usually just
increasing <code>acceptCount</code> will solve that problem.
Increasing this value may also be beneficial when a large amount of send file
operations are going on.
</p>
</attribute>
<attribute name="pollerThreadPriority" required="false">
<p>(int)The priority of the poller threads.
The default value is <code>5</code> (the value of the
<code>java.lang.Thread.NORM_PRIORITY</code> constant). See the JavaDoc
for the <code>java.lang.Thread</code> class for more details on what
this priority means.</p>
</attribute>
<attribute name="selectorTimeout" required="false">
<p>(int)The time in milliseconds to timeout on a select() for the
poller. This value is important, since connection clean up is done on
the same thread, so do not set this value to an extremely high one. The
default value is <code>1000</code> milliseconds.</p>
</attribute>
<attribute name="useSendfile" required="false">
<p>(bool)Use this attribute to enable or disable sendfile capability.
The default value is <code>true</code>. Note that the use of sendfile
will disable any compression that Tomcat may otherwise have performed on
the response.</p>
</attribute>
<attribute name="socket.directBuffer" required="false">
<p>(bool)Boolean value, whether to use direct ByteBuffers or java mapped
ByteBuffers. If <code>true</code> then
<code>java.nio.ByteBuffer.allocateDirect()</code> is used to allocate
the buffers, if <code>false</code> then
<code>java.nio.ByteBuffer.allocate()</code> is used. The default value
is <code>false</code>.<br/>
When you are using direct buffers, make sure you allocate the
appropriate amount of memory for the direct memory space. On Sun's JDK
that would be something like <code>-XX:MaxDirectMemorySize=256m</code>.
</p>
</attribute>
<attribute name="socket.directSslBuffer" required="false">
<p>(bool)Boolean value, whether to use direct ByteBuffers or java mapped
ByteBuffers for the SSL buffers. If <code>true</code> then
<code>java.nio.ByteBuffer.allocateDirect()</code> is used to allocate
the buffers, if <code>false</code> then
<code>java.nio.ByteBuffer.allocate()</code> is used. The default value
is <code>false</code>.<br/>
When you are using direct buffers, make sure you allocate the
appropriate amount of memory for the direct memory space. On Oracle's JDK
that would be something like <code>-XX:MaxDirectMemorySize=256m</code>.
</p>
</attribute>
<attribute name="socket.appReadBufSize" required="false">
<p>(int)Each connection that is opened up in Tomcat get associated with
a read ByteBuffer. This attribute controls the size of this buffer. By
default this read buffer is sized at <code>8192</code> bytes. For lower
concurrency, you can increase this to buffer more data. For an extreme
amount of keep alive connections, decrease this number or increase your
heap size.</p>
</attribute>
<attribute name="socket.appWriteBufSize" required="false">
<p>(int)Each connection that is opened up in Tomcat get associated with
a write ByteBuffer. This attribute controls the size of this buffer. By
default this write buffer is sized at <code>8192</code> bytes. For low
concurrency you can increase this to buffer more response data. For an
extreme amount of keep alive connections, decrease this number or
increase your heap size.<br/>
The default value here is pretty low, you should up it if you are not
dealing with tens of thousands concurrent connections.</p>
</attribute>
<attribute name="socket.bufferPool" required="false">
<p>(int)The NIO connector uses a class called NioChannel that holds
elements linked to a socket. To reduce garbage collection, the NIO
connector caches these channel objects. This value specifies the size of
this cache. The default value is <code>500</code>, and represents that
the cache will hold 500 NioChannel objects. Other values are
<code>-1</code> for unlimited cache and <code>0</code> for no cache.</p>
</attribute>
<attribute name="socket.bufferPoolSize" required="false">
<p>(int)The NioChannel pool can also be size based, not used object
based. The size is calculated as follows:<br/>
NioChannel
<code>buffer size = read buffer size + write buffer size</code><br/>
SecureNioChannel <code>buffer size = application read buffer size +
application write buffer size + network read buffer size +
network write buffer size</code><br/>
The value is in bytes, the default value is <code>1024*1024*100</code>
(100MB).</p>
</attribute>
<attribute name="socket.processorCache" required="false">
<p>(int)Tomcat will cache SocketProcessor objects to reduce garbage
collection. The integer value specifies how many objects to keep in the
cache at most. The default is <code>500</code>. Other values are
<code>-1</code> for unlimited cache and <code>0</code> for no cache.</p>
</attribute>
<attribute name="socket.keyCache" required="false">
<p>(int)Tomcat will cache KeyAttachment objects to reduce garbage
collection. The integer value specifies how many objects to keep in the
cache at most. The default is <code>500</code>. Other values are
<code>-1</code> for unlimited cache and <code>0</code> for no cache.</p>
</attribute>
<attribute name="socket.eventCache" required="false">
<p>(int)Tomcat will cache PollerEvent objects to reduce garbage
collection. The integer value specifies how many objects to keep in the
cache at most. The default is <code>500</code>. Other values are
<code>-1</code> for unlimited cache and <code>0</code> for no cache.</p>
</attribute>
<attribute name="selectorPool.maxSelectors" required="false">
<p>(int)The max selectors to be used in the pool, to reduce selector
contention. Use this option when the command line
<code>org.apache.tomcat.util.net.NioSelectorShared</code> value is set
to false. Default value is <code>200</code>.</p>
</attribute>
<attribute name="selectorPool.maxSpareSelectors" required="false">
<p>(int)The max spare selectors to be used in the pool, to reduce
selector contention. When a selector is returned to the pool, the system
can decide to keep it or let it be GC'd. Use this option when the
command line <code>org.apache.tomcat.util.net.NioSelectorShared</code>
value is set to false. Default value is <code>-1</code> (unlimited).</p>
</attribute>
<attribute name="useInheritedChannel" required="false">
<p>(bool)Defines if this connector should inherit an inetd/systemd network socket.
Only one connector can inherit a network socket. This can option can be
used to automatcially start Tomcat once a connection request is made to
the systemd super daemon's port.
The default value is <code>false</code>. See the JavaDoc
for the <code>java.nio.channels.spi.SelectorProvider</code> class for
more details.</p>
</attribute>
<attribute name="command-line-options" required="false">
<p>The following command line options are available for the NIO
connector:<br/>
<code>-Dorg.apache.tomcat.util.net.NioSelectorShared=true|false</code>
- default is <code>true</code>. Set this value to <code>false</code> if you wish to
use a selector for each thread. When you set it to <code>false</code>, you can
control the size of the pool of selectors by using the
<strong>selectorPool.maxSelectors</strong> attribute.</p>
</attribute>
</attributes>
</subsection>
<subsection name="NIO2 specific configuration">
<p>The following attributes are specific to the NIO2 connector.</p>
<attributes>
<attribute name="useSendfile" required="false">
<p>(bool)Use this attribute to enable or disable sendfile capability.
The default value is <code>true</code>. Note that the use of sendfile
will disable any compression that Tomcat may otherwise have performed on
the response.</p>
</attribute>
<attribute name="socket.directBuffer" required="false">
<p>(bool)Boolean value, whether to use direct ByteBuffers or java mapped
ByteBuffers. If <code>true</code> then
<code>java.nio.ByteBuffer.allocateDirect()</code> is used to allocate
the buffers, if <code>false</code> then
<code>java.nio.ByteBuffer.allocate()</code> is used. The default value
is <code>false</code>.<br/>
When you are using direct buffers, make sure you allocate the
appropriate amount of memory for the direct memory space. On Sun's JDK
that would be something like <code>-XX:MaxDirectMemorySize=256m</code>.
</p>
</attribute>
<attribute name="socket.directSslBuffer" required="false">
<p>(bool)Boolean value, whether to use direct ByteBuffers or java mapped
ByteBuffers for the SSL buffers. If <code>true</code> then
<code>java.nio.ByteBuffer.allocateDirect()</code> is used to allocate
the buffers, if <code>false</code> then
<code>java.nio.ByteBuffer.allocate()</code> is used. The default value
is <code>false</code>.<br/>
When you are using direct buffers, make sure you allocate the
appropriate amount of memory for the direct memory space. On Oracle's JDK
that would be something like <code>-XX:MaxDirectMemorySize=256m</code>.
</p>
</attribute>
<attribute name="socket.appReadBufSize" required="false">
<p>(int)Each connection that is opened up in Tomcat get associated with
a read ByteBuffer. This attribute controls the size of this buffer. By
default this read buffer is sized at <code>8192</code> bytes. For lower
concurrency, you can increase this to buffer more data. For an extreme
amount of keep alive connections, decrease this number or increase your
heap size.</p>
</attribute>
<attribute name="socket.appWriteBufSize" required="false">
<p>(int)Each connection that is opened up in Tomcat get associated with
a write ByteBuffer. This attribute controls the size of this buffer. By
default this write buffer is sized at <code>8192</code> bytes. For low
concurrency you can increase this to buffer more response data. For an
extreme amount of keep alive connections, decrease this number or
increase your heap size.<br/>
The default value here is pretty low, you should up it if you are not
dealing with tens of thousands concurrent connections.</p>
</attribute>
<attribute name="socket.bufferPool" required="false">
<p>(int)The NIO2 connector uses a class called Nio2Channel that holds
elements linked to a socket. To reduce garbage collection, the NIO2
connector caches these channel objects. This value specifies the size of
this cache. The default value is <code>500</code>, and represents that
the cache will hold 500 Nio2Channel objects. Other values are
<code>-1</code> for unlimited cache and <code>0</code> for no cache.</p>
</attribute>
<attribute name="socket.processorCache" required="false">
<p>(int)Tomcat will cache SocketProcessor objects to reduce garbage
collection. The integer value specifies how many objects to keep in the
cache at most. The default is <code>500</code>. Other values are
<code>-1</code> for unlimited cache and <code>0</code> for no cache.</p>
</attribute>
</attributes>
</subsection>
<subsection name="APR/native specific configuration">
<p>The following attributes are specific to the APR/native connector.</p>
<attributes>
<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="ipv6v6only" required="false">
<p>If listening on an IPv6 address on a dual stack system, should the
connector only listen on the IPv6 address? If not specified the default
is <code>false</code> and the connector will listen on the IPv6 address
and the equivalent IPv4 address if present.</p>
</attribute>
<attribute name="pollerThreadCount" required="false">
<p>Number of threads used to poll kept alive connections. On Windows the
default is chosen so that the sockets managed by each thread is
less than 1024. For Linux the default is 1. Changing the default on
Windows is likely to have a negative performance impact.</p>
</attribute>
<attribute name="pollTime" required="false">
<p>Duration of a poll call in microseconds. Lowering this value will
slightly decrease latency of connections being kept alive in some cases,
but will use more CPU as more poll calls are being made. The default
value is 2000 (2ms).</p>
</attribute>
<attribute name="sendfileSize" required="false">
<p>Amount of sockets that the poller responsible for sending static
files asynchronously can hold at a given time. Extra connections will be
closed right away without any data being sent (resulting in a zero
length file on the client side). Note that in most cases, sendfile is a
call that will return right away (being taken care of "synchronously" by
the kernel), and the sendfile poller will not be used, so the amount of
static files which can be sent concurrently is much larger than the
specified amount. The default value is 1024.</p>
</attribute>
<attribute name="threadPriority" required="false">
<p>(int)The priority of the acceptor and poller threads.
The default value is <code>5</code> (the value of the
<code>java.lang.Thread.NORM_PRIORITY</code> constant). See the JavaDoc
for the <code>java.lang.Thread</code> class for more details on what
this priority means.</p>
</attribute>
<attribute name="useSendfile" required="false">
<p>(bool)Use this attribute to enable or disable sendfile capability.
The default value is <code>true</code>. Note that the use of sendfile
will disable any compression that Tomcat may otherwise have performed on
the response.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="Nested Components">
<p>First implemented in Tomcat 9 and back-ported to 8.5, Tomcat now supports
Server Name Indication (SNI). This allows multiple SSL configurations to be
associated with a single secure connector with the configuration used for any
given connection determined by the host name requested by the client. To
facilitate this, the <strong>SSLHostConfig</strong> element was added which
can be used to define one of these configurations. Any number of
<strong>SSLHostConfig</strong> may be nested in a <strong>Connector</strong>.
At the same time, support was added for multiple certificates to be associated
with a single <strong>SSLHostConfig</strong>. Each SSL certificate is
therefore configured in a <strong>Certificate</strong> element with in an
<strong>SSLHostConfig</strong>. For further information, see the SSL Support
section below.</p>
</section>
<section name="Special Features">
<subsection name="HTTP/1.1 and HTTP/1.0 Support">
<p>This <strong>Connector</strong> supports all of the required features
of the HTTP/1.1 protocol, as described in RFCs 7230-7235, including persistent
connections, pipelining, expectations and chunked encoding. If the client
supports only HTTP/1.0 or HTTP/0.9, the
<strong>Connector</strong> will gracefully fall back to supporting this
protocol as well. No special configuration is required to enable this
support. The <strong>Connector</strong> also supports HTTP/1.0
keep-alive.</p>
<p>RFC 7230 requires that HTTP servers always begin their responses with
the highest HTTP version that they claim to support. Therefore, this
<strong>Connector</strong> will always return <code>HTTP/1.1</code> at
the beginning of its responses.</p>
</subsection>
<subsection name="HTTP/2 Support">
<p>HTTP/2 is support is provided for TLS (h2), non-TLS via HTTP upgrade (h2c)
and direct HTTP/2 (h2c) connections. To enable HTTP/2 support for an HTTP
connector the following <strong>UpgradeProtocol</strong> element must be
nested within the <strong>Connector</strong> with a
<strong>className</strong> attribute of
<code>org.apache.coyote.http2.Http2Protocol</code>.</p>
<source><![CDATA[<Connector ... >
<UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol" />
</Connector>]]></source>
<p>Because Java 8's TLS implementation does not support ALPN (which is
required for HTTP/2 over TLS), you must be using an OpenSSL based TLS
implementation to enable HTTP/2 support. See the
<code>sslImplementationName</code> attribute of the
<strong>Connector</strong>.</p>
<p>Additional configuration attributes are available. See the
<a href="http2.html">HTTP/2 Upgrade Protocol</a> documentation for details.</p>
</subsection>
<subsection name="Proxy Support">
<p>The <code>proxyName</code> and <code>proxyPort</code> attributes can
be used when Tomcat is run behind a proxy server. These attributes
modify the values returned to web applications that call the
<code>request.getServerName()</code> and <code>request.getServerPort()</code>
methods, which are often used to construct absolute URLs for redirects.
Without configuring these attributes, the values returned would reflect
the server name and port on which the connection from the proxy server
was received, rather than the server name and port to whom the client
directed the original request.</p>
<p>For more information, see the
<a href="../proxy-howto.html">Proxy Support How-To</a>.</p>
</subsection>
<subsection name="SSL Support">
<p>You can enable SSL support for a particular instance of this
<strong>Connector</strong> by setting the <code>SSLEnabled</code> attribute to
<code>true</code>.</p>
<p>You will also need to set the <code>scheme</code> and <code>secure</code>
attributes to the values <code>https</code> and <code>true</code>
respectively, to pass correct information to the servlets.</p>
<p>The NIO and NIO2 connectors use either the JSSE Java SSL implementation or
an OpenSSL implementation, whereas the APR/native connector uses OpenSSL only.
Prior to Tomcat 8.5, different configuration attributes were used for JSSE and
OpenSSL. From Tomcat 8.5 onwards, and as far as possible, common configuration
attributes are used for both JSSE and OpenSSL. Also if using the JSSE OpenSSL
implementation, configuration can be set using either the JSSE or APR
attributes (note: but not both types within the same configuration). This is
to aid simpler switching between connector implementations for SSL
connectors.</p>
<p>Each secure connector must define at least one
<strong>SSLHostConfig</strong>. The names of the
<strong>SSLHostConfig</strong> elements must be unique and one of them must
match the <code>defaultSSLHostConfigName</code> attribute of the
<strong>Connector</strong>.</p>
<p>Each <strong>SSLHostConfig</strong> must in turn define at least one
<strong>Certificate</strong>. The types of the <strong>Certificate</strong>s
must be unique.</p>
<p>As of Tomcat 8.5, the majority of the SSL configuration attributes in the
<strong>Connector</strong> are deprecated. If specified, they will be used to
configure a <strong>SSLHostConfig</strong> and <strong>Certificate</strong>
for the <code>defaultSSLHostConfigName</code>. Note that if an explicit
<strong>SSLHostConfig</strong> element also exists for the
<code>defaultSSLHostConfigName</code> then that will be treated as a configuration
error. It is expected that Tomcat 10 will drop support for the SSL
configuration attributes in the <strong>Connector</strong>.</p>
<p>For more information, see the
<a href="../ssl-howto.html">SSL Configuration How-To</a>.</p>
</subsection>
<subsection name="SSL Support - SSLHostConfig">
<p></p>
<attributes>
<attribute name="certificateRevocationListFile" required="false">
<p>Name of the file that contains the concatenated certificate revocation
lists for the certificate authorities. The format is PEM-encoded. If not
defined, client certificates will not be checked against a certificate
revocation list (unless an OpenSSL based connector is used and
<strong>certificateRevocationListPath</strong> is defined). Relative paths
will be resolved against <code>$CATALINA_BASE</code>. JSSE based
connectors may also specify a URL for this attribute.</p>
</attribute>
<attribute name="certificateRevocationListPath" required="false">
<p>OpenSSL only.</p>
<p>Name of the directory that contains the certificate revocation lists
for the certificate authorities. The format is PEM-encoded. Relative paths
will be resolved against <code>$CATALINA_BASE</code>.</p>
</attribute>
<attribute name="certificateVerification" required="false">
<p>Set to <code>required</code> if you want the SSL stack to require a
valid certificate chain from the client before accepting a connection.
Set to <code>optional</code> if you want the SSL stack to request a client
Certificate, but not fail if one isn't presented. Set to
<code>optionalNoCA</code> if you want client certificates to be optional
and you don't want Tomcat to check them against the list of trusted CAs.
If the TLS provider doesn't support this option (OpenSSL does, JSSE does
not) it is treated as if <code>optional</code> was specified. A
<code>none</code> value (which is the default) will not require a
certificate chain unless the client requests a resource protected by a
security constraint that uses <code>CLIENT-CERT</code> authentication.</p>
</attribute>
<attribute name="certificateVerificationDepth" required="false">
<p>The maximum number of intermediate certificates that will be allowed
when validating client certificates. If not specified, the default value
of 10 will be used.</p>
</attribute>
<attribute name="caCertificateFile" required="false">
<p>OpenSSL only.</p>
<p>Name of the file that contains the concatenated certificates for the
trusted certificate authorities. The format is PEM-encoded.</p>
</attribute>
<attribute name="caCertificatePath" required="false">
<p>OpenSSL only.</p>
<p>Name of the directory that contains the certificates for the trusted
certificate authorities. The format is PEM-encoded.</p>
</attribute>
<attribute name="ciphers" required="false">
<p>The ciphers to enable using the OpenSSL syntax. (See the OpenSSL
documentation for the list of ciphers supported and the syntax).
Alternatively, a comma separated list of ciphers using the standard
OpenSSL cipher names or the standard JSSE cipher names may be used.</p>
<p>When converting from OpenSSL syntax to JSSE ciphers for JSSE based
connectors, the behaviour of the OpenSSL syntax parsing is kept aligned
with the behaviour of the OpenSSL 1.1.0 development branch.</p>
<p>Only the ciphers that are supported by the SSL implementation will be
used.</p>
<p>If not specified, a default (using the OpenSSL notation) of
<code>HIGH:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!kRSA</code> will be
used.</p>
<p>Note that, by default, the order in which ciphers are defined is
treated as an order of preference. See <code>honorCipherOrder</code>.</p>
</attribute>
<attribute name="disableCompression" required="false">
<p>OpenSSL only.</p>
<p>Configures if compression is disabled. The default is
<code>true</code>. If the OpenSSL version used does not support disabling
compression then the default for that OpenSSL version will be used.</p>
</attribute>
<attribute name="disableSessionTickets" required="false">
<p>OpenSSL only.</p>
<p>Disables use of TLS session tickets (RFC 5077) if set to
<code>true</code>. Default is <code>false</code>. Note that when TLS
session tickets are in use, the full peer certificate chain will only be
available on the first connection. Subsequent connections (that use a
ticket to estrablish the TLS session) will only have the peer certificate,
not the full chain.</p>
</attribute>
<attribute name="honorCipherOrder" required="false">
<p>Set to <code>true</code> to enforce the server's cipher order
(from the <code>ciphers</code> setting) instead of allowing
the client to choose the cipher. The default is <code>false</code>.</p>
</attribute>
<attribute name="hostName" required="false">
<p>The name of the SSL Host. This should either be the fully qualified
domain name (e.g. <code>tomcat.apache.org</code>) or a wild card domain
name (e.g. <code>*.apache.org</code>). If not specified, the default value
of <code>_default_</code> will be used.</p>
</attribute>
<attribute name="insecureRenegotiation" required="false">
<p>OpenSSL only.</p>
<p>Configures if insecure renegotiation is allowed. The default is
<code>false</code>. If the OpenSSL version used does not support
configuring if insecure renegotiation is allowed then the default for that
OpenSSL version will be used.</p>
</attribute>
<attribute name="keyManagerAlgorithm" required="false">
<p>JSSE only.</p>
<p>The <code>KeyManager</code> algorithm to be used. This defaults to
<code>KeyManagerFactory.getDefaultAlgorithm()</code> which returns
<code>SunX509</code> for Sun JVMs. IBM JVMs return
<code>IbmX509</code>. For other vendors, consult the JVM
documentation for the default value.</p>
</attribute>
<attribute name="protocols" required="false">
<p>The names of the protocols to support when communicating with clients.
This should be a list of any combination of the following:
</p>
<ul><li>SSLv2Hello</li><li>SSLv3</li><li>TLSv1</li><li>TLSv1.1</li>
<li>TLSv1.2</li><li>TLSv1.3</li><li>all</li></ul>
<p>Each token in the list can be prefixed with a plus sign ("+")
or a minus sign ("-"). A plus sign adds the protocol, a minus sign
removes it form the current list. The list is built starting from
an empty list.</p>
<p>The token <code>all</code> is an alias for
<code>SSLv2Hello,TLSv1,TLSv1.1,TLSv1.2,TLSv1.3</code>.</p>
<p>Note that <code>TLSv1.3</code> is only supported for JSSE when using a
JVM that implements <code>TLSv1.3</code>.</p>
<p>Note that <code>SSLv2Hello</code> will be ignored for OpenSSL based
secure connectors. If more than one protocol is specified for an OpenSSL
based secure connector it will always support <code>SSLv2Hello</code>. If a
single protocol is specified it will not support
<code>SSLv2Hello</code>.</p>
<p>Note that <code>SSLv2</code> and <code>SSLv3</code> are inherently
unsafe.</p>
<p>If not specified, the default value of <code>all</code> will be
used.</p>
</attribute>
<attribute name="revocationEnabled" required="false">
<p>JSSE only.</p>
<p>Should the JSSE provider enable certificate revocation checks? If
<strong>certificateRevocationListFile</strong> is set then this attribute
is ignored and revocation checks are always enabled. This attribute is
intended to enable revocation checks that have been configured for the
current JSSE provider via other means. If not specified, a default of
<code>false</code> is used.</p>
</attribute>
<attribute name="sessionCacheSize" required="false">
<p>JSSE only.</p>
<p>The number of SSL sessions to maintain in the session cache. Use 0 to
specify an unlimited cache size. If not specified, a default of 0 is
used.</p>
</attribute>
<attribute name="sessionTimeout" required="false">
<p>JSSE only.</p>
<p>The time, in seconds, after the creation of an SSL session that it will
timeout. Use 0 to specify an unlimited timeout. If not specified, a
default of 86400 (24 hours) is used.</p>
</attribute>
<attribute name="sslProtocol" required="false">
<p>JSSE only.</p>
<p>The SSL protocol(s) to use (a single value may enable multiple
protocols - see the JVM documentation for details). If not specified, the
default is <code>TLS</code>. The permitted values may be obtained from the
JVM documentation for the allowed values for algorithm when creating an
<code>SSLContext</code> instance e.g.
<a href="http://docs.oracle.com/javase/7/docs/technotes/guides/security/StandardNames.html#SSLContext">
Oracle Java 7</a>. Note: There is overlap between this attribute and
<code>protocols</code>.</p>
</attribute>
<attribute name="trustManagerClassName" required="false">
<p>JSSE only.</p>
<p>The name of a custom trust manager class to use to validate client
certificates. The class must have a zero argument constructor and must
also implement <code>javax.net.ssl.X509TrustManager</code>. If this
attribute is set, the trust store attributes may be ignored.</p>
</attribute>
<attribute name="truststoreAlgorithm" required="false">
<p>JSSE only.</p>
<p>The algorithm to use for truststore. If not specified, the default
value returned by
<code>javax.net.ssl.TrustManagerFactory.getDefaultAlgorithm()</code> is
used.</p>
</attribute>
<attribute name="truststoreFile" required="false">
<p>JSSE only.</p>
<p>The trust store file to use to validate client certificates. The
default is the value of the <code>javax.net.ssl.trustStore</code> system
property. If neither this attribute nor the default system property is
set, no trust store will be configured. Relative paths
will be resolved against <code>$CATALINA_BASE</code>. A URL may also be
used for this attribute.</p>
</attribute>
<attribute name="truststorePassword" required="false">
<p>JSSE only.</p>
<p>The password to access the trust store. The default is the value of the
<code>javax.net.ssl.trustStorePassword</code> system property. If that
property is null, no trust store password will be configured. If an
invalid trust store password is specified, a warning will be logged and an
attempt will be made to access the trust store without a password which
will skip validation of the trust store contents.</p>
</attribute>
<attribute name="truststoreProvider" required="false">
<p>JSSE only.</p>
<p>The name of the truststore provider to be used for the server
certificate. The default is the value of the
<code>javax.net.ssl.trustStoreProvider</code> system property. If
that property is null, the value of <code>keystoreProvider</code> is used
as the default. If neither this attribute, the default system property nor
<code>keystoreProvider</code> is set, the list of registered providers is
traversed in preference order and the first provider that supports the
<code>truststoreType</code> is used.
</p>
</attribute>
<attribute name="truststoreType" required="false">
<p>JSSE only.</p>
<p>The type of key store used for the trust store. The default is the
value of the <code>javax.net.ssl.trustStoreType</code> system property. If
that property is null, a single certificate has been configured for this
TLS virtual host and that certificate has a <code>keystoreType</code> that
is not <code>PKCS12</code> then the default will be the
<code>keystoreType</code> of the single certificate. If none of these
identify a default, the default will be <code>JKS</code>.</p>
</attribute>
</attributes>
</subsection>
<subsection name="SSL Support - Certificate">
<p></p>
<attributes>
<attribute name="certificateFile" required="true">
<p>Name of the file that contains the server certificate. The format is
PEM-encoded. Relative paths will be resolved against
<code>$CATALINA_BASE</code>.</p>
<p>In addition to the certificate, the file can also contain as optional
elements DH parameters and/or an EC curve name for ephemeral keys, as
generated by <code>openssl dhparam</code> and <code>openssl ecparam</code>,
respectively. The output of the respective OpenSSL command can simply
be concatenated to the certificate file.</p>
</attribute>
<attribute name="certificateChainFile" required="false">
<p>Name of the file that contains the certificate chain associated with
the server certificate used. The format is
PEM-encoded. Relative paths will be resolved against
<code>$CATALINA_BASE</code>.</p>
<p>The certificate chain used for Tomcat should not include the server
certificate as its first element.</p>
<p>Note that when using more than one certificate for different types,
they all must use the same certificate chain.</p>
</attribute>
<attribute name="certificateKeyAlias" required="false">
<p>JSSE only.</p>
<p>The alias used for the server key and certificate in the keystore. If
not specified, the first key read from the keystore will be used. The
order in which keys are read from the keystore is implementation
dependent. It may not be the case that keys are read from the keystore in
the same order as they were added. If more than one key is present in the
keystore it is strongly recommended that a keyAlias is configured to
ensure that the correct key is used.</p>
</attribute>
<attribute name="certificateKeyFile" required="false">
<p>Name of the file that contains the server private key. The format is
PEM-encoded. The default value is the value of
<strong>certificateFile</strong> and in this case both certificate and
private key have to be in this file (NOT RECOMMENDED). Relative paths will
be resolved against <code>$CATALINA_BASE</code>.</p>
</attribute>
<attribute name="certificateKeyPassword" required="false">
<p>The password used to access the private key associated with the server
certificate from the specified file.</p>
<p>If not specified, the default behaviour for JSSE is to use the
<strong>certificateKeystorePassword</strong>. For OpenSSL the default
behaviour is not to use a password.</p>
</attribute>
<attribute name="certificateKeystoreFile" required="false">
<p>JSSE only.</p>
<p>The pathname of the keystore file where you have stored the server
certificate and key to be loaded. By default, the pathname is the file
<code>.keystore</code> in the operating system home directory of the user
that is running Tomcat. If your <code>keystoreType</code> doesn't need a
file use <code>""</code> (empty string) or <code>NONE</code> for this
parameter. Relative paths will be resolved against
<code>$CATALINA_BASE</code>. A URI may also be used for this attribute.
When using a domain keystore (<code>keystoreType</code> of
<code>DKS</code>), this parameter should be the URI to the domain
keystore.</p>
</attribute>
<attribute name="certificateKeystorePassword" required="false">
<p>JSSE only.</p>
<p>The password to use to access the keystore containing the server&apos;s
private key and certificate. If not specified, a default of
<code>changeit</code> will be used.</p>
</attribute>
<attribute name="certificateKeystoreProvider" required="false">
<p>JSSE only.</p>
<p>The name of the keystore provider to be used for the server
certificate. If not specified, the value of the system property
<code>javax.net.ssl.keyStoreProvider</code> is used. If neither this
attribute nor the system property are set, the list of registered
providers is traversed in preference order and the first provider that
supports the <code>keystoreType</code> is used.
</p>
</attribute>
<attribute name="certificateKeystoreType" required="false">
<p>JSSE only.</p>
<p>The type of keystore file to be used for the server certificate.
If not specified, the value of the system property
<code>javax.net.ssl.keyStoreType</code> is used. If neither this attribute
nor the system property are set, a default value of "<code>JKS</code>". is
used.</p>
</attribute>
<attribute name="type" required="false">
<p>The type of certificate. This is used to identify the ciphers that are
compatible with the certificate. It must be one of <code>UNDEFINED</code>,
<code>RSA</code>, <code>DSS</code> or <code>EC</code>. If only one
<strong>Certificate</strong> is nested within a <code>SSLHostConfig</code>
then this attribute is not required and will default to
<code>UNDEFINED</code>. If multiple <strong>Certificate</strong>s are
nested within a <code>SSLHostConfig</code> then this attribute is required
and each <strong>Certificate</strong> must have a unique type.</p>
</attribute>
</attributes>
</subsection>
<subsection name="SSL Support - Connector - NIO and NIO2">
<p>When APR/native is enabled, the connectors will default to using OpenSSL through JSSE,
which may be more optimized than the JSSE Java implementation depending on the processor being used,
and can be complemented with many commercial accelerator components.</p>
<p>The following NIO and NIO2 SSL configuration attributes are not specific to
a virtual host and, therefore, must be configured on the connector.</p>
<attributes>
<attribute name="sniParseLimit" required="false">
<p>In order to implement SNI support, Tomcat has to parse the first TLS
message received on a new TLS connection (the client hello) to extract the
requested server name. The message needs to be buffered so it can then be
passed to the JSSE implementation for normal TLS processing. In theory,
this first message could be very large although in practice it is
typically a few hundred bytes. This attribute sets the maximum message
size that Tomcat will buffer. If a message exceeds this size, the
connection will be configured as if no server name was indicated by the
client. If not specified a default of <code>65536</code> (64k) will be
used.</p>
</attribute>
<attribute name="sslImplementationName" required="false">
<p>The class name of the SSL implementation to use. If not specified and
the tomcat-native library is not installed, the
default of <code>org.apache.tomcat.util.net.jsse.JSSEImplementation</code>
will be used which wraps JVM&apos;s default JSSE provider. Note that the
JVM can be configured to use a different JSSE provider as the default.
Tomcat also bundles a special SSL implementation for JSSE that is backed
by OpenSSL. To enable it, the native library should be enabled as if
intending to use the APR connector, and Tomcat will automatically enable it
and the default value of this attribute becomes
<code>org.apache.tomcat.util.net.openssl.OpenSSLImplementation</code>.
In that case, the attributes from either JSSE and OpenSSL
configuration styles can be used, as long as the two types are not mixed
(for example, it is not allowed to define use of a Java keystore and
specify a separate pem private key using the OpenSSL attribute).</p>
</attribute>
</attributes>
</subsection>
<subsection name="SSL Support - Connector - NIO and NIO2 (deprecated)">
<p>The following NIO and NIO2 SSL configuration attributes have been
deprecated in favor of the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.
</p>
<attributes>
<attribute name="algorithm" required="false">
<p>This is an alias for the <code>keyManagerAlgorithm</code> attribute of
the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="ciphers" required="false">
<p>This is an alias for the <code>ciphers</code> attribute of the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="clientAuth" required="false">
<p>This is an alias for the <code>certificateVerification</code> attribute
of the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="crlFile" required="false">
<p>This is an alias for the <code>certificateRevocationListFile</code>
attribute of the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="keyAlias" required="false">
<p>This is an alias for the <code>certificateKeyAlias</code> attribute of
the first <a href="#SSL_Support_-_Certificate">Certificate</a> element
nested in the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="keyPass" required="false">
<p>This is an alias for the <code>certificateKeyPassword</code> attribute
of the first <a href="#SSL_Support_-_Certificate">Certificate</a> element
nested in the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="keystoreFile" required="false">
<p>This is an alias for the <code>certificateKeystoreFile</code> attribute
of the first <a href="#SSL_Support_-_Certificate">Certificate</a> element
nested in the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="keystorePass" required="false">
<p>This is an alias for the <code>certificateKeystorePassword</code>
attribute of the first
<a href="#SSL_Support_-_Certificate">Certificate</a> element nested in the
default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="keystoreProvider" required="false">
<p>This is an alias for the <code>certificateKeystoreProvider</code>
attribute of the first
<a href="#SSL_Support_-_Certificate">Certificate</a> element nested in the
default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="keystoreType" required="false">
<p>This is an alias for the <code>certificateKeystoreType</code> attribute
of the first <a href="#SSL_Support_-_Certificate">Certificate</a> element
nested in the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="sessionCacheSize" required="false">
<p>This is an alias for the <code>sessionCacheSize</code> attribute of the
default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="sessionTimeout" required="false">
<p>This is an alias for the <code>sessionTimeout</code> attribute of the
default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="sslEnabledProtocols" required="false">
<p>This is an alias for the <code>protocols</code> attribute of the
default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="sslProtocol" required="false">
<p>This is an alias for the <code>sslProtocol</code> attribute of the
default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="trustManagerClassName" required="false">
<p>This is an alias for the <code>trustManagerClassName</code> attribute
of the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="trustMaxCertLength" required="false">
<p>This is an alias for the <code>certificateVerificationDepth</code>
attribute of the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="truststoreAlgorithm" required="false">
<p>This is an alias for the <code>truststoreAlgorithm</code> attribute of
the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="truststoreFile" required="false">
<p>This is an alias for the <code>truststoreFile</code> attribute of
the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="truststorePass" required="false">
<p>This is an alias for the <code>truststorePassword</code> attribute of
the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="truststoreProvider" required="false">
<p>This is an alias for the <code>truststoreProvider</code> attribute of
the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="truststoreType" required="false">
<p>This is an alias for the <code>truststoreType</code> attribute of
the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="useServerCipherSuitesOrder" required="false">
<p>This is an alias for the <code>honorCipherOrder</code> attribute of the
default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
</attributes>
</subsection>
<subsection name="SSL Support - Connector - APR/Native (deprecated)">
<p>When APR/native is enabled, the HTTPS connector will use a socket poller
for keep-alive, increasing scalability of the server. It also uses OpenSSL,
which may be more optimized than JSSE depending on the processor being used,
and can be complemented with many commercial accelerator components. Unlike
the HTTP connector, the HTTPS connector cannot use sendfile to optimize static
file processing.</p>
<p>The HTTPS APR/native connector has the same attributes than the HTTP
APR/native connector, but adds OpenSSL specific ones. For the full details on
using OpenSSL, please refer to OpenSSL documentations and the many books
available for it (see the <a href="http://www.openssl.org">Official OpenSSL
website</a>). The SSL specific attributes for the APR/native connector are:
</p>
<attributes>
<attribute name="SSLCACertificateFile" required="false">
<p>This is an alias for the <code>caCertificateFile</code>
attribute of the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="SSLCACertificatePath" required="false">
<p>This is an alias for the <code>caCertificatePath</code>
attribute of the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="SSLCARevocationFile" required="false">
<p>This is an alias for the <code>certificateRevocationListFile</code>
attribute of the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="SSLCARevocationPath" required="false">
<p>This is an alias for the <code>certificateRevocationListPath</code>
attribute of the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="SSLCertificateFile" required="true">
<p>This is an alias for the <code>certificateFile</code> attribute of the
first <a href="#SSL_Support_-_Certificate">Certificate</a> element nested
in the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="SSLCertificateKeyFile" required="false">
<p>This is an alias for the <code>certificateKeyFile</code> attribute of the
first <a href="#SSL_Support_-_Certificate">Certificate</a> element nested
in the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="SSLCipherSuite" required="false">
<p>This is an alias for the <code>ciphers</code> attribute of the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="SSLDisableCompression" required="false">
<p>This is an alias for the <code>disableCompression</code> attribute of
the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="SSLHonorCipherOrder" required="false">
<p>This is an alias for the <code>honorCipherOrder</code> attribute of the
default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="SSLPassword" required="false">
<p>This is an alias for the <code>certificateKeyPassword</code> attribute
of the first <a href="#SSL_Support_-_Certificate">Certificate</a> element
nested in the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="SSLProtocol" required="false">
<p>This is an alias for the <code>protocols</code> attribute of the
default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="SSLVerifyClient" required="false">
<p>This is an alias for the <code>certificateVerification</code> attribute
of the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
<attribute name="SSLVerifyDepth" required="false">
<p>This is an alias for the <code>certificateVerificationDepth</code>
attribute of the default
<a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a> element.</p>
</attribute>
<attribute name="SSLDisableSessionTickets" required="false">
<p>This is an alias for the <code>disableSessionTickets</code> attribute
of the default <a href="#SSL_Support_-_SSLHostConfig">SSLHostConfig</a>
element.</p>
</attribute>
</attributes>
</subsection>
<subsection name="Connector Comparison">
<p>Below is a small chart that shows how the connectors differ.</p>
<table class="defaultTable" style="text-align: center;">
<tr>
<th />
<th style="text-align: center;">Java Nio Connector<br />NIO</th>
<th style="text-align: center;">Java Nio2 Connector<br />NIO2</th>
<th style="text-align: center;">APR/native Connector<br />APR</th>
</tr>
<tr>
<th>Classname</th>
<td><code class="noHighlight">Http11NioProtocol</code></td>
<td><code class="noHighlight">Http11Nio2Protocol</code></td>
<td><code class="noHighlight">Http11AprProtocol</code></td>
</tr>
<tr>
<th>Tomcat Version</th>
<td>6.x onwards</td>
<td>8.x onwards</td>
<td>5.5.x onwards</td>
</tr>
<tr>
<th>Support Polling</th>
<td>YES</td>
<td>YES</td>
<td>YES</td>
</tr>
<tr>
<th>Polling Size</th>
<td><code class="noHighlight">maxConnections</code></td>
<td><code class="noHighlight">maxConnections</code></td>
<td><code class="noHighlight">maxConnections</code></td>
</tr>
<tr>
<th>Read Request Headers</th>
<td>Non Blocking</td>
<td>Non Blocking</td>
<td>Non Blocking</td>
</tr>
<tr>
<th>Read Request Body</th>
<td>Blocking</td>
<td>Blocking</td>
<td>Blocking</td>
</tr>
<tr>
<th>Write Response Headers and Body</th>
<td>Blocking</td>
<td>Blocking</td>
<td>Blocking</td>
</tr>
<tr>
<th>Wait for next Request</th>
<td>Non Blocking</td>
<td>Non Blocking</td>
<td>Non Blocking</td>
</tr>
<tr>
<th>SSL Support</th>
<td>Java SSL or OpenSSL</td>
<td>Java SSL or OpenSSL</td>
<td>OpenSSL</td>
</tr>
<tr>
<th>SSL Handshake</th>
<td>Non blocking</td>
<td>Non blocking</td>
<td>Blocking</td>
</tr>
<tr>
<th>Max Connections</th>
<td><code class="noHighlight">maxConnections</code></td>
<td><code class="noHighlight">maxConnections</code></td>
<td><code class="noHighlight">maxConnections</code></td>
</tr>
</table>
</subsection>
</section>
</body>
</document>