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view xml/en/docs/mail/ngx_mail_ssl_module.xml @ 2245:87a0e2c73a25
Refactored njs documentation.
author | Yaroslav Zhuravlev <yar@nginx.com> |
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date | Mon, 24 Sep 2018 19:10:29 +0300 |
parents | 3535437f97d2 |
children | e2e71f9477a8 |
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<?xml version="1.0"?> <!-- Copyright (C) 2006, 2007 Anton Yuzhaninov Copyright (C) Nginx, Inc. --> <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd"> <module name="Module ngx_mail_ssl_module" link="/en/docs/mail/ngx_mail_ssl_module.html" lang="en" rev="18"> <section id="summary"> <para> The <literal>ngx_mail_ssl_module</literal> module provides the necessary support for a mail proxy server to work with the SSL/TLS protocol. </para> <para> This module is not built by default, it should be enabled with the <literal>--with-mail_ssl_module</literal> configuration parameter. <note> This module requires the <link url="http://www.openssl.org">OpenSSL</link> library. </note> </para> </section> <section id="example" name="Example Configuration"> <para> To reduce the processor load, it is recommended to <list type="bullet"> <listitem> set the number of <link doc="../ngx_core_module.xml" id="worker_processes">worker processes</link> equal to the number of processors, </listitem> <listitem> enable the <link id="ssl_session_cache_shared">shared</link> session cache, </listitem> <listitem> disable the <link id="ssl_session_cache_builtin">built-in</link> session cache, </listitem> <listitem> and possibly increase the session <link id="ssl_session_timeout">lifetime</link> (by default, 5 minutes): </listitem> </list> <example> <emphasis>worker_processes auto;</emphasis> mail { ... server { listen 993 ssl; ssl_protocols TLSv1 TLSv1.1 TLSv1.2; ssl_ciphers AES128-SHA:AES256-SHA:RC4-SHA:DES-CBC3-SHA:RC4-MD5; ssl_certificate /usr/local/nginx/conf/cert.pem; ssl_certificate_key /usr/local/nginx/conf/cert.key; <emphasis>ssl_session_cache shared:SSL:10m;</emphasis> <emphasis>ssl_session_timeout 10m;</emphasis> ... } </example> </para> </section> <section id="directives" name="Directives"> <directive name="ssl"> <syntax><literal>on</literal> | <literal>off</literal></syntax> <default>off</default> <context>mail</context> <context>server</context> <para> This directive was made obsolete in version 1.15.0. The <literal>ssl</literal> parameter of the <link doc="ngx_mail_core_module.xml" id="listen"/> directive should be used instead. </para> </directive> <directive name="ssl_certificate"> <syntax><value>file</value></syntax> <default/> <context>mail</context> <context>server</context> <para> Specifies a <value>file</value> with the certificate in the PEM format for the given server. If intermediate certificates should be specified in addition to a primary certificate, they should be specified in the same file in the following order: the primary certificate comes first, then the intermediate certificates. A secret key in the PEM format may be placed in the same file. </para> <para> Since version 1.11.0, this directive can be specified multiple times to load certificates of different types, for example, RSA and ECDSA: <example> server { listen 993 ssl; ssl_certificate example.com.rsa.crt; ssl_certificate_key example.com.rsa.key; ssl_certificate example.com.ecdsa.crt; ssl_certificate_key example.com.ecdsa.key; ... } </example> <note> Only OpenSSL 1.0.2 or higher supports separate certificate chains for different certificates. With older versions, only one certificate chain can be used. </note> </para> </directive> <directive name="ssl_certificate_key"> <syntax><value>file</value></syntax> <default/> <context>mail</context> <context>server</context> <para> Specifies a <value>file</value> with the secret key in the PEM format for the given server. </para> <para> The value <literal>engine</literal>:<value>name</value>:<value>id</value> can be specified instead of the <value>file</value> (1.7.9), which loads a secret key with a specified <value>id</value> from the OpenSSL engine <value>name</value>. </para> </directive> <directive name="ssl_ciphers"> <syntax><value>ciphers</value></syntax> <default>HIGH:!aNULL:!MD5</default> <context>mail</context> <context>server</context> <para> Specifies the enabled ciphers. The ciphers are specified in the format understood by the OpenSSL library, for example: <example> ssl_ciphers ALL:!aNULL:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP; </example> </para> <para> The full list can be viewed using the “<command>openssl ciphers</command>” command. </para> <para> <note> The previous versions of nginx used <link doc="../http/configuring_https_servers.xml" id="compatibility">different</link> ciphers by default. </note> </para> </directive> <directive name="ssl_client_certificate"> <syntax><value>file</value></syntax> <default/> <context>mail</context> <context>server</context> <appeared-in>1.7.11</appeared-in> <para> Specifies a <value>file</value> with trusted CA certificates in the PEM format used to <link id="ssl_verify_client">verify</link> client certificates. </para> <para> The list of certificates will be sent to clients. If this is not desired, the <link id="ssl_trusted_certificate"/> directive can be used. </para> </directive> <directive name="ssl_crl"> <syntax><value>file</value></syntax> <default/> <context>mail</context> <context>server</context> <appeared-in>1.7.11</appeared-in> <para> Specifies a <value>file</value> with revoked certificates (CRL) in the PEM format used to <link id="ssl_verify_client">verify</link> client certificates. </para> </directive> <directive name="ssl_dhparam"> <syntax><value>file</value></syntax> <default/> <context>mail</context> <context>server</context> <appeared-in>0.7.2</appeared-in> <para> Specifies a <value>file</value> with DH parameters for DHE ciphers. </para> </directive> <directive name="ssl_ecdh_curve"> <syntax><value>curve</value></syntax> <default>auto</default> <context>mail</context> <context>server</context> <appeared-in>1.1.0</appeared-in> <appeared-in>1.0.6</appeared-in> <para> Specifies a <value>curve</value> for ECDHE ciphers. </para> <para> When using OpenSSL 1.0.2 or higher, it is possible to specify multiple curves (1.11.0), for example: <example> ssl_ecdh_curve prime256v1:secp384r1; </example> </para> <para> The special value <literal>auto</literal> (1.11.0) instructs nginx to use a list built into the OpenSSL library when using OpenSSL 1.0.2 or higher, or <literal>prime256v1</literal> with older versions. </para> <para> <note> Prior to version 1.11.0, the <literal>prime256v1</literal> curve was used by default. </note> </para> </directive> <directive name="ssl_password_file"> <syntax><value>file</value></syntax> <default/> <context>mail</context> <context>server</context> <appeared-in>1.7.3</appeared-in> <para> Specifies a <value>file</value> with passphrases for <link id="ssl_certificate_key">secret keys</link> where each passphrase is specified on a separate line. Passphrases are tried in turn when loading the key. </para> <para> Example: <example> mail { ssl_password_file /etc/keys/global.pass; ... server { server_name mail1.example.com; ssl_certificate_key /etc/keys/first.key; } server { server_name mail2.example.com; # named pipe can also be used instead of a file ssl_password_file /etc/keys/fifo; ssl_certificate_key /etc/keys/second.key; } } </example> </para> </directive> <directive name="ssl_prefer_server_ciphers"> <syntax><literal>on</literal> | <literal>off</literal></syntax> <default>off</default> <context>mail</context> <context>server</context> <para> Specifies that server ciphers should be preferred over client ciphers when the SSLv3 and TLS protocols are used. </para> </directive> <directive name="ssl_protocols"> <syntax> [<literal>SSLv2</literal>] [<literal>SSLv3</literal>] [<literal>TLSv1</literal>] [<literal>TLSv1.1</literal>] [<literal>TLSv1.2</literal>] [<literal>TLSv1.3</literal>]</syntax> <default>TLSv1 TLSv1.1 TLSv1.2</default> <context>mail</context> <context>server</context> <para> Enables the specified protocols. <note> The <literal>TLSv1.1</literal> and <literal>TLSv1.2</literal> parameters (1.1.13, 1.0.12) work only when OpenSSL 1.0.1 or higher is used. </note> <note> The <literal>TLSv1.3</literal> parameter (1.13.0) works only when OpenSSL 1.1.1 built with TLSv1.3 support is used. </note> </para> </directive> <directive name="ssl_session_cache"> <syntax> <literal>off</literal> | <literal>none</literal> | [<literal>builtin</literal>[:<value>size</value>]] [<literal>shared</literal>:<value>name</value>:<value>size</value>]</syntax> <default>none</default> <context>mail</context> <context>server</context> <para> Sets the types and sizes of caches that store session parameters. A cache can be of any of the following types: <list type="tag"> <tag-name><literal>off</literal></tag-name> <tag-desc> the use of a session cache is strictly prohibited: nginx explicitly tells a client that sessions may not be reused. </tag-desc> <tag-name><literal>none</literal></tag-name> <tag-desc> the use of a session cache is gently disallowed: nginx tells a client that sessions may be reused, but does not actually store session parameters in the cache. </tag-desc> <tag-name id="ssl_session_cache_builtin"><literal>builtin</literal></tag-name> <tag-desc> a cache built in OpenSSL; used by one worker process only. The cache size is specified in sessions. If size is not given, it is equal to 20480 sessions. Use of the built-in cache can cause memory fragmentation. </tag-desc> <tag-name id="ssl_session_cache_shared"><literal>shared</literal></tag-name> <tag-desc> a cache shared between all worker processes. The cache size is specified in bytes; one megabyte can store about 4000 sessions. Each shared cache should have an arbitrary name. A cache with the same name can be used in several servers. </tag-desc> </list> </para> <para> Both cache types can be used simultaneously, for example: <example> ssl_session_cache builtin:1000 shared:SSL:10m; </example> but using only shared cache without the built-in cache should be more efficient. </para> </directive> <directive name="ssl_session_ticket_key"> <syntax><value>file</value></syntax> <default/> <context>mail</context> <context>server</context> <appeared-in>1.5.7</appeared-in> <para> Sets a <value>file</value> with the secret key used to encrypt and decrypt TLS session tickets. The directive is necessary if the same key has to be shared between multiple servers. By default, a randomly generated key is used. </para> <para> If several keys are specified, only the first key is used to encrypt TLS session tickets. This allows configuring key rotation, for example: <example> ssl_session_ticket_key current.key; ssl_session_ticket_key previous.key; </example> </para> <para> The <value>file</value> must contain 80 or 48 bytes of random data and can be created using the following command: <example> openssl rand 80 > ticket.key </example> Depending on the file size either AES256 (for 80-byte keys, 1.11.8) or AES128 (for 48-byte keys) is used for encryption. </para> </directive> <directive name="ssl_session_tickets"> <syntax><literal>on</literal> | <literal>off</literal></syntax> <default>on</default> <context>mail</context> <context>server</context> <appeared-in>1.5.9</appeared-in> <para> Enables or disables session resumption through <link url="https://tools.ietf.org/html/rfc5077">TLS session tickets</link>. </para> </directive> <directive name="ssl_session_timeout"> <syntax><value>time</value></syntax> <default>5m</default> <context>mail</context> <context>server</context> <para> Specifies a time during which a client may reuse the session parameters. </para> </directive> <directive name="ssl_trusted_certificate"> <syntax><value>file</value></syntax> <default/> <context>mail</context> <context>server</context> <appeared-in>1.7.11</appeared-in> <para> Specifies a <value>file</value> with trusted CA certificates in the PEM format used to <link id="ssl_verify_client">verify</link> client certificates. </para> <para> In contrast to the certificate set by <link id="ssl_client_certificate"/>, the list of these certificates will not be sent to clients. </para> </directive> <directive name="ssl_verify_client"> <syntax> <literal>on</literal> | <literal>off</literal> | <literal>optional</literal> | <literal>optional_no_ca</literal></syntax> <default>off</default> <context>mail</context> <context>server</context> <appeared-in>1.7.11</appeared-in> <para> Enables verification of client certificates. The verification result is passed in the <header>Auth-SSL-Verify</header> header of the <link doc="ngx_mail_auth_http_module.xml" id="auth_http">authentication</link> request. </para> <para> The <literal>optional</literal> parameter requests the client certificate and verifies it if the certificate is present. </para> <para> The <literal>optional_no_ca</literal> parameter requests the client certificate but does not require it to be signed by a trusted CA certificate. This is intended for the use in cases when a service that is external to nginx performs the actual certificate verification. The contents of the certificate is accessible through requests <link doc="ngx_mail_auth_http_module.xml" id="auth_http_pass_client_cert">sent</link> to the authentication server. </para> </directive> <directive name="ssl_verify_depth"> <syntax><value>number</value></syntax> <default>1</default> <context>mail</context> <context>server</context> <appeared-in>1.7.11</appeared-in> <para> Sets the verification depth in the client certificates chain. </para> </directive> <directive name="starttls"> <syntax> <literal>on</literal> | <literal>off</literal> | <literal>only</literal></syntax> <default>off</default> <context>mail</context> <context>server</context> <para> <list type="tag"> <tag-name><literal>on</literal></tag-name> <tag-desc> allow usage of the <literal>STLS</literal> command for the POP3 and the <literal>STARTTLS</literal> command for the IMAP and SMTP; </tag-desc> <tag-name><literal>off</literal></tag-name> <tag-desc> deny usage of the <literal>STLS</literal> and <literal>STARTTLS</literal> commands; </tag-desc> <tag-name><literal>only</literal></tag-name> <tag-desc> require preliminary TLS transition. </tag-desc> </list> </para> </directive> </section> </module>