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<tr><td><code>SSL_SRP_USERINFO</code></td> <td>string</td> <td>SRP user info</td></tr>
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<trclass="odd"><td><code>SSL_TLS_SNI</code></td> <td>string</td> <td>Contents of the SNI TLS extension (if supplied with ClientHello)</td></tr>
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<tr><td><code>SSL_HANDSHAKE_RTT</code></td> <td>number</td> <td>Round-trip time of TLS handshake in microseconds including endpoint processing (set to empty string if OpenSSL version prior to 3.2 or if round-trip time can not be determined)</td></tr>
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<trclass="odd"><td><code>SSL_CLIENTHELLO_VERSION</code></td> <td>string</td> <td>Version field (legacy) from ClientHello as four hex encoded characters</td></tr>
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<tr><td><code>SSL_CLIENTHELLO_CIPHERS</code></td> <td>string</td> <td>Cipher Suites from ClientHello as four hex encoded characters per item</td></tr>
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<trclass="odd"><td><code>SSL_CLIENTHELLO_EXTENSIONS</code></td> <td>string</td> <td>Extension IDs from ClientHello as four hex encoded characters per item</td></tr>
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<tr><td><code>SSL_CLIENTHELLO_GROUPS</code></td> <td>string</td> <td>Value of Supported Groups extension (10) from ClientHello as four hex encoded characters per item</td></tr>
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<trclass="odd"><td><code>SSL_CLIENTHELLO_EC_FORMATS</code></td> <td>string</td> <td>Value of EC Point Formats extension (11) from ClientHello as two hex encoded characters per item</td></tr>
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<tr><td><code>SSL_CLIENTHELLO_SIG_ALGOS</code></td> <td>string</td> <td>Value of Signature Algorithms extension (13) from ClientHello as four hex encoded characters per item</td></tr>
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<trclass="odd"><td><code>SSL_CLIENTHELLO_ALPN</code></td> <td>string</td> <td>Value of ALPN extension (16) from ClientHello as hex encoded string including leading string lengths</td></tr>
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<tr><td><code>SSL_CLIENTHELLO_VERSIONS</code></td> <td>string</td> <td>Value of Supported Versions extension (43) from ClientHello as four hex encoded characters per item</td></tr>
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</table>
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<p><em>x509</em> specifies a component of an X.509 DN; one of
@@ -230,6 +239,10 @@ suffix (if any). For example, <code>SSL_SERVER_S_DN_OU_RAW</code> or
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<p><code>SSL_CLIENT_V_REMAIN</code> is only available in version 2.1
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and later.</p>
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<p>The <code>SSL_CLIENTHELLO_*</code> variables require the directive
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<codeclass="directive"><ahref="#sslclienthellovars">SSLClientHelloVars</a></code> to be
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enabled or they will not be populated.</p>
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<p>A number of additional environment variables can also be used
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in <codeclass="directive">SSLRequire</code> expressions, or in custom log
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formats:</p>
@@ -625,9 +638,10 @@ If using a PEM file, at minimum, the file must include an end-entity (leaf) cert
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The directive can be used multiple times (referencing different filenames)
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to support multiple algorithms for server authentication - typically
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RSA, DSA, and ECC. The number of supported algorithms depends on the
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OpenSSL version being used for mod_ssl: with version 1.0.0 or later,
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<code>openssl list-public-key-algorithms</code> will output a list
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of supported algorithms, see also the note below about limitations
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OpenSSL version being used for mod_ssl: with version 3.0 or later,
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<code>openssl list -public-key-algorithms</code> (or
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<code>openssl list-public-key-algorithms</code> with OpenSSL 1.0) will output a list
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of supported algorithms. See the note below about limitations
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of OpenSSL versions prior to 1.0.2 and the ways to work around them.
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</p>
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@@ -677,7 +691,7 @@ Beginning with version 2.4.7, mod_ssl makes use of
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standardized DH parameters with prime lengths of 2048, 3072 and 4096 bits
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and with additional prime lengths of 6144 and 8192 bits beginning with
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version 2.4.10
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(from <ahref="http://www.ietf.org/rfc/rfc3526.txt">RFC 3526</a>), and hands
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(from <ahref="https://www.rfc-editor.org/rfc/rfc3526">RFC 3526</a>), and hands
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them out to clients based on the length of the certificate's RSA/DSA key.
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With Java-based clients in particular (Java 7 or earlier), this may lead
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to handshake failures - see this
@@ -796,7 +810,7 @@ Since TLSv1.3 does not offer renegotiations, specifying ciphers for it in
<tr><th><ahref="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in httpd 2.5.2 and later, requires OpenSSL 1.1.1 or later</td></tr>
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</table>
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<p>This directive enables collection of ClientHello data during the handshake that is retained for
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the length of the connection so it can be exposed as <code>SSL_CLIENTHELLLO_*</code> environment
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variables for requests depending upon the <code>StdEnvVars</code> setting. The variables are
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formatted as the hex-encoded raw buffers seen in the raw network protocol and as provided
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by OpenSSL. GREASE (RFC 8701) values are filtered by OpenSSL when enumerating extension IDs, but
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otherwise, are passed through unchanged for other variables. If this directive is not enabled or
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if OpenSSL prior to version 1.1.1 is used, these variables will not have a value set.</p>
@@ -1295,7 +1288,7 @@ features are added to OpenSSL.</p>
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depends on the OpenSSL version being used for <codeclass="module"><ahref="../mod/mod_ssl.html">mod_ssl</a></code>
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(at least version 1.0.2 is required). For a list of supported command
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names, see the section <em>Supported configuration file commands</em> in the
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<ahref="http://www.openssl.org/docs/man1.0.2/ssl/SSL_CONF_cmd.html#SUPPORTED-CONFIGURATION-FILE-COMMANDS">SSL_CONF_cmd(3)</a> manual page for OpenSSL.</p>
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<ahref="https://docs.openssl.org/master/man3/SSL_CONF_cmd/#supported-configuration-file-commands">SSL_CONF_cmd(3)</a> manual page for OpenSSL.</p>
@@ -2950,7 +2943,7 @@ var comments_identifier = 'http://httpd.apache.org/docs/trunk/mod/mod_ssl.html';
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}
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})(window, document);
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//--><!]]></script></div><divid="footer">
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<pclass="apache">Copyright 2023 The Apache Software Foundation.<br />Licensed under the <ahref="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
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<pclass="apache">Copyright 2025 The Apache Software Foundation.<br />Licensed under the <ahref="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
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