| Deployment GuideHTTP (Hypertext Transfer Protocol) server, or a web server, is a network service that serves content to a client over the web. This typically means web pages, but any other documents can be served as well.
15.1. The Apache HTTP ServerThis section focuses on the Apache HTTP Server 2.2, a robust, full-featured open source web server developed by the Apache Software Foundation, that is included in Red Hat Enterprise Linux 6. It describes the basic configuration of the httpd service, and covers advanced topics such as adding server modules, setting up virtual hosts, or configuring the secure HTTP server. There are important differences between the Apache HTTP Server 2.2 and version 2.0, and if you are upgrading from a previous release of Red Hat Enterprise Linux, you will need to update the httpd service configuration accordingly. This section reviews some of the newly added features, outlines important changes, and guides you through the update of older configuration files. The Apache HTTP Server version 2.2 introduces the following enhancements: Improved caching modules, that is, mod_cache and mod_disk_cache. Support for proxy load balancing, that is, the mod_proxy_balancer module. Support for large files on 32-bit architectures, allowing the web server to handle files greater than 2GB. A new structure for authentication and authorization support, replacing the authentication modules provided in previous versions.
Since version 2.0, few changes have been made to the default httpd service configuration: The following modules are no longer loaded by default: mod_cern_meta and mod_asis. The following module is newly loaded by default: mod_ext_filter.
15.1.3. Updating the ConfigurationTo update the configuration files from the Apache HTTP Server version 2.0, take the following steps: Make sure all module names are correct, since they may have changed. Adjust the LoadModule directive for each module that has been renamed. Recompile all third party modules before attempting to load them. This typically means authentication and authorization modules. If you use the mod_userdir module, make sure the UserDir directive indicating a directory name (typically public_html) is provided. If you use the Apache HTTP Secure Server, edit the /etc/httpd/conf.d/ssl.conf to enable the Secure Sockets Layer (SSL) protocol.
Note that you can check the configuration for possible errors by using the following command: ~]# service httpd configtestSyntax OK 15.1.4. Running the httpd ServiceThis section describes how to start, stop, restart, and check the current status of the Apache HTTP Server. To be able to use the httpd service, make sure you have the httpd installed. You can do so by using the following command: ~]# yum install httpd For more information on the concept of runlevels and how to manage system services in Red Hat Enterprise Linux in general, refer to Chapter 10, Services and Daemons. 15.1.4.1. Starting the ServiceTo run the httpd service, type the following at a shell prompt: ~]# service httpd startStarting httpd: [ OK ] If you want the service to start automatically at the boot time, use the following command: ~]# chkconfig httpd on If running the Apache HTTP Server as a secure server, a password may be required after the machine boots if using an encrypted private SSL key. 15.1.4.2. Stopping the ServiceTo stop the running httpd service, type the following at a shell prompt: ~]# service httpd stopStopping httpd: [ OK ] To prevent the service from starting automatically at the boot time, type: ~]# chkconfig httpd off 15.1.4.3. Restarting the ServiceThere are three different ways to restart the running httpd service: To restart the service completely, type: ~]# service httpd restartStopping httpd: [ OK ]Starting httpd: [ OK ] This will stop the running httpd service, and then start it again. Use this command after installing or removing a dynamically loaded module such as PHP. To only reload the configuration, type: ~]# service httpd reload This will cause the running httpd service to reload the configuration file. Note that any requests being currently processed will be interrupted, which may cause a client browser to display an error message or render a partial page. To reload the configuration without affecting active requests, type: ~]# service httpd graceful This will cause the running httpd service to reload the configuration file. Note that any requests being currently processed will use the old configuration.
15.1.4.4. Checking the Service StatusTo check whether the service is running, type the following at a shell prompt: ~]# service httpd statushttpd (pid 19014) is running... 15.1.5. Editing the Configuration FilesTable 15.1. The httpd service configuration files | Path | Description |
|---|
/etc/httpd/conf/httpd.conf | The main configuration file. | /etc/httpd/conf.d/ | An auxiliary directory for configuration files that are included in the main configuration file. |
Although the default configuration should be suitable for most situations, it is a good idea to become at least familiar with some of the more important configuration options. Note that for any changes to take effect, the web server has to be restarted first. Refer to Section 15.1.4.3, "Restarting the Service" for more information on how to restart the httpd service. To check the configuration for possible errors, type the following at a shell prompt: ~]# service httpd configtestSyntax OK To make the recovery from mistakes easier, it is recommended that you make a copy of the original file before editing it. 15.1.5.1. Common httpd.conf DirectivesThe following directives are commonly used in the /etc/httpd/conf/httpd.conf configuration file: -
<Directory> The <Directory> directive allows you to apply certain directives to a particular directory only. It takes the following form: <Directory directory> directive . . . . . . </Directory> The directory can be either a full path to an existing directory in the local file system, or a wildcard expression. This directive can be used to configure additional cgi-bin directories for server-side scripts located outside the directory that is specified by ScriptAlias. In this case, the ExecCGI and AddHandler directives must be supplied, and the permissions on the target directory must be set correctly (that is, 0755). Example 15.1. Using the <Directory> directive <Directory /var/www/html> Options Indexes FollowSymLinks AllowOverride None Order allow,deny Allow from all</Directory>
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<IfDefine> The IfDefine directive allows you to use certain directives only when a particular parameter is supplied on the command line. It takes the following form: <IfDefine [!]parameter> directive . . . . . . </IfDefine> The parameter can be supplied at a shell prompt using the -Dparameter command line option (for example, httpd -DEnableHome). If the optional exclamation mark (that is, !) is present, the enclosed directives are used only when the parameter is not specified. Example 15.2. Using the <IfDefine> directive <IfDefine EnableHome> UserDir public_html</IfDefine>
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<IfModule> The <IfModule> directive allows you to use certain directive only when a particular module is loaded. It takes the following form: <IfModule [!]module> directive . . . . . . </IfModule> The module can be identified either by its name, or by the file name. If the optional exclamation mark (that is, !) is present, the enclosed directives are used only when the module is not loaded. Example 15.3. Using the <IfModule> directive <IfModule mod_disk_cache.c> CacheEnable disk / CacheRoot /var/cache/mod_proxy</IfModule>
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<Location> The <Location> directive allows you to apply certain directives to a particular URL only. It takes the following form: <Location url> directive . . . . . . </Location> The url can be either a path relative to the directory specified by the DocumentRoot directive (for example, /server-info), or an external URL such as http://example.com/server-info. Example 15.4. Using the <Location> directive <Location /server-info> SetHandler server-info Order deny,allow Deny from all Allow from .example.com</Location>
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<Proxy> The <Proxy> directive allows you to apply certain directives to the proxy server only. It takes the following form: <Proxy pattern> directive . . . . . . </Proxy> The pattern can be an external URL, or a wildcard expression (for example, http://example.com/*). Example 15.5. Using the <Proxy> directive <Proxy *> Order deny,allow Deny from all Allow from .example.com</Proxy>
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<VirtualHost> The <VirtualHost> directive allows you apply certain directives to particular virtual hosts only. It takes the following form: <VirtualHost address[:port] . . . . . . > directive . . . . . . </VirtualHost> Table 15.2. Available <VirtualHost> options | Option | Description |
|---|
* | Represents all IP addresses. | _default_ | Represents unmatched IP addresses. |
Example 15.6. Using the <VirtualHost> directive <VirtualHost *:80> ServerAdmin [email protected] DocumentRoot /www/docs/penguin.example.com ServerName penguin.example.com ErrorLog logs/penguin.example.com-error_log CustomLog logs/penguin.example.com-access_log common</VirtualHost>
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AccessFileName The AccessFileName directive allows you to specify the file to be used to customize access control information for each directory. It takes the following form: AccessFileName filename . . . . . . The filename is a name of the file to look for in the requested directory. By default, the server looks for .htaccess. For security reasons, the directive is typically followed by the Files tag to prevent the files beginning with .ht from being accessed by web clients. This includes the .htaccess and .htpasswd files. Example 15.7. Using the AccessFileName directive AccessFileName .htaccess<Files ~ "^\.ht"> Order allow,deny Deny from all Satisfy All</Files>
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Action The Action directive allows you to specify a CGI script to be executed when a certain media type is requested. It takes the following form: Action content-type path The content-type has to be a valid MIME type such as text/html, image/png, or application/pdf. The path refers to an existing CGI script, and must be relative to the directory specified by the DocumentRoot directive (for example, /cgi-bin/process-image.cgi). Example 15.8. Using the Action directive Action image/png /cgi-bin/process-image.cgi
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AddDescription The AddDescription directive allows you to specify a short description to be displayed in server-generated directory listings for a given file. It takes the following form: AddDescription "description" filename . . . . . . The description should be a short text enclosed in double quotes (that is, "). The filename can be a full file name, a file extension, or a wildcard expression. Example 15.9. Using the AddDescription directive AddDescription "GZIP compressed tar archive" .tgz
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AddEncoding The AddEncoding directive allows you to specify an encoding type for a particular file extension. It takes the following form: AddEncoding encoding extension . . . . . . The encoding has to be a valid MIME encoding such as x-compress, x-gzip, etc. The extension is a case sensitive file extension, and is conventionally written with a leading dot (for example, .gz). This directive is typically used to instruct web browsers to decompress certain file types as they are downloaded. Example 15.10. Using the AddEncoding directive AddEncoding x-gzip .gz .tgz
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AddHandler The AddHandler directive allows you to map certain file extensions to a selected handler. It takes the following form: AddHandler handler extension . . . . . . The handler has to be a name of a previously defined handler. The extension is a case sensitive file extension, and is conventionally written with a leading dot (for example, .cgi). This directive is typically used to treat files with the .cgi extension as CGI scripts regardless of the directory they are in. Additionally, it is also commonly used to process server-parsed HTML and image-map files. Example 15.11. Using the AddHandler option AddHandler cgi-script .cgi
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AddIcon The AddIcon directive allows you to specify an icon to be displayed for a particular file in server-generated directory listings. It takes the following form: AddIcon path pattern . . . . . . The path refers to an existing icon file, and must be relative to the directory specified by the DocumentRoot directive (for example, /icons/folder.png). The pattern can be a file name, a file extension, a wildcard expression, or a special form as described in the following table: Table 15.3. Available AddIcon options | Option | Description |
|---|
^^DIRECTORY^^ | Represents a directory. | ^^BLANKICON^^ | Represents a blank line. |
Example 15.12. Using the AddIcon directive AddIcon /icons/text.png .txt README
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AddIconByEncoding The AddIconByEncoding directive allows you to specify an icon to be displayed for a particular encoding type in server-generated directory listings. It takes the following form: AddIconByEncoding path encoding . . . . . . The path refers to an existing icon file, and must be relative to the directory specified by the DocumentRoot directive (for example, /icons/compressed.png). The encoding has to be a valid MIME encoding such as x-compress, x-gzip, etc. Example 15.13. Using the AddIconByEncoding directive AddIconByEncoding /icons/compressed.png x-compress x-gzip
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AddIconByType The AddIconByType directive allows you to specify an icon to be displayed for a particular media type in server-generated directory listings. It takes the following form: AddIconByType path content-type . . . . . . The path refers to an existing icon file, and must be relative to the directory specified by the DocumentRoot directive (for example, /icons/text.png). The content-type has to be either a valid MIME type (for example, text/html or image/png), or a wildcard expression such as text/*, image/*, etc. Example 15.14. Using the AddIconByType directive AddIconByType /icons/video.png video/*
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AddLanguage The AddLanguage directive allows you to associate a file extension with a specific language. It takes the following form: AddLanguage language extension . . . . . . The language has to be a valid MIME language such as cs, en, or fr. The extension is a case sensitive file extension, and is conventionally written with a leading dot (for example, .cs). This directive is especially useful for web servers that serve content in multiple languages based on the client's language settings. Example 15.15. Using the AddLanguage directive
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AddType The AddType directive allows you to define or override the media type for a particular file extension. It takes the following form: AddType content-type extension . . . . . . The content-type has to be a valid MIME type such as text/html, image/png, etc. The extension is a case sensitive file extension, and is conventionally written with a leading dot (for example, .cs). Example 15.16. Using the AddType directive AddType application/x-gzip .gz .tgz
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Alias The Alias directive allows you to refer to files and directories outside the default directory specified by the DocumentRoot directive. It takes the following form: Alias url-path real-path The url-path must be relative to the directory specified by the DocumentRoot directive (for example, /images/). The real-path is a full path to a file or directory in the local file system. This directive is typically followed by the Directory tag with additional permissions to access the target directory. By default, the /icons/ alias is created so that the icons from /var/www/icons/ are displayed in server-generated directory listings. Example 15.17. Using the Alias directive Alias /icons/ /var/www/icons/<Directory "/var/www/icons"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order allow,deny Allow from all<Directory>
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Allow The Allow directive allows you to specify which clients have permission to access a given directory. It takes the following form: Allow from client . . . . . . The client can be a domain name, an IP address (both full and partial), a network/netmask pair, or all for all clients. Example 15.18. Using the Allow directive Allow from 192.168.1.0/255.255.255.0
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AllowOverride The AllowOverride directive allows you to specify which directives in a .htaccess file can override the default configuration. It takes the following form: AllowOverride type . . . . . . Table 15.4. Available AllowOverride options | Option | Description |
|---|
All | All directives in .htaccess are allowed to override earlier configuration settings. | None | No directive in .htaccess is allowed to override earlier configuration settings. | AuthConfig | Allows the use of authorization directives such as AuthName, AuthType, or Require. | FileInfo | Allows the use of file type, metadata, and mod_rewrite directives such as DefaultType, RequestHeader, or RewriteEngine, as well as the Action directive. | Indexes | Allows the use of directory indexing directives such as AddDescription, AddIcon, or FancyIndexing. | Limit | Allows the use of host access directives, that is, Allow, Deny, and Order. | Options [=option, . . . . . . ] | Allows the use of the Options directive. Additionally, you can provide a comma-separated list of options to customize which options can be set using this directive. |
Example 15.19. Using the AllowOverride directive AllowOverride FileInfo AuthConfig Limit
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BrowserMatch The BrowserMatch directive allows you to modify the server behavior based on the client's web browser type. It takes the following form: BrowserMatch pattern variable . . . . . . The pattern is a regular expression to match the User-Agent HTTP header field. The variable is an environment variable that is set when the header field matches the pattern. By default, this directive is used to deny connections to specific browsers with known issues, and to disable keepalives and HTTP header flushes for browsers that are known to have problems with these actions. Example 15.20. Using the BrowserMatch directive BrowserMatch "Mozilla/2" nokeepalive
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CacheDefaultExpire The CacheDefaultExpire option allows you to set how long to cache a document that does not have any expiration date or the date of its last modification specified. It takes the following form: CacheDefaultExpire time The time is specified in seconds. The default option is 3600 (that is, one hour). Example 15.21. Using the CacheDefaultExpire directive
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CacheDisable The CacheDisable directive allows you to disable caching of certain URLs. It takes the following form: CacheDisable path The path must be relative to the directory specified by the DocumentRoot directive (for example, /files/). Example 15.22. Using the CacheDisable directive
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CacheEnable The CacheEnable directive allows you to specify a cache type to be used for certain URLs. It takes the following form: CacheEnable type url The type has to be a valid cache type as described in Table 15.5, "Available cache types". The url can be a path relative to the directory specified by the DocumentRoot directive (for example, /images/), a protocol (for example, ftp://), or an external URL such as http://example.com/. Table 15.5. Available cache types | Type | Description |
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mem | The memory-based storage manager. | disk | The disk-based storage manager. | fd | The file descriptor cache. |
Example 15.23. Using the CacheEnable directive
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CacheLastModifiedFactor The CacheLastModifiedFactor directive allows you to customize how long to cache a document that does not have any expiration date specified, but that provides information about the date of its last modification. It takes the following form: CacheLastModifiedFactor number The number is a coefficient to be used to multiply the time that passed since the last modification of the document. The default option is 0.1 (that is, one tenth). Example 15.24. Using the CacheLastModifiedFactor directive CacheLastModifiedFactor 0.1
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CacheMaxExpire The CacheMaxExpire directive allows you to specify the maximum amount of time to cache a document. It takes the following form: CacheMaxExpire time The time is specified in seconds. The default option is 86400 (that is, one day). Example 15.25. Using the CacheMaxExpire directive
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CacheNegotiatedDocs The CacheNegotiatedDocs directive allows you to enable caching of the documents that were negotiated on the basis of content. It takes the following form: CacheNegotiatedDocs option Table 15.6. Available CacheNegotiatedDocs options | Option | Description |
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On | Enables caching the content-negotiated documents. | Off | Disables caching the content-negotiated documents. |
Example 15.26. Using the CacheNegotiatedDocs directive
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CacheRoot The CacheRoot directive allows you to specify the directory to store cache files in. It takes the following form: CacheRoot directory The directory must be a full path to an existing directory in the local file system. The default option is /var/cache/mod_proxy/. Example 15.27. Using the CacheRoot directive CacheRoot /var/cache/mod_proxy
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CustomLog The CustomLog directive allows you to specify the log file name and the log file format. It takes the following form: CustomLog path format The path refers to a log file, and must be relative to the directory that is specified by the ServerRoot directive (that is, /etc/httpd/ by default). The format has to be either an explicit format string, or a format name that was previously defined using the LogFormat directive. Example 15.28. Using the CustomLog directive CustomLog logs/access_log combined
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DefaultIcon The DefaultIcon directive allows you to specify an icon to be displayed for a file in server-generated directory listings when no other icon is associated with it. It takes the following form: DefaultIcon path The path refers to an existing icon file, and must be relative to the directory specified by the DocumentRoot directive (for example, /icons/unknown.png). Example 15.29. Using the DefaultIcon directive DefaultIcon /icons/unknown.png
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DefaultType The DefaultType directive allows you to specify a media type to be used in case the proper MIME type cannot be determined by the server. It takes the following form: DefaultType content-type The content-type has to be a valid MIME type such as text/html, image/png, application/pdf, etc. Example 15.30. Using the DefaultType directive
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Deny The Deny directive allows you to specify which clients are denied access to a given directory. It takes the following form: Deny from client . . . . . . The client can be a domain name, an IP address (both full and partial), a network/netmask pair, or all for all clients. Example 15.31. Using the Deny directive
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DirectoryIndex The DirectoryIndex directive allows you to specify a document to be served to a client when a directory is requested (that is, when the URL ends with the / character). It takes the following form: DirectoryIndex filename . . . . . . The filename is a name of the file to look for in the requested directory. By default, the server looks for index.html, and index.html.var. Example 15.32. Using the DirectoryIndex directive DirectoryIndex index.html index.html.var
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DocumentRoot The DocumentRoot directive allows you to specify the main directory from which the content is served. It takes the following form: DocumentRoot directory The directory must be a full path to an existing directory in the local file system. The default option is /var/www/html/. Example 15.33. Using the DocumentRoot directive DocumentRoot /var/www/html
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ErrorDocument The ErrorDocument directive allows you to specify a document or a message to be displayed as a response to a particular error. It takes the following form: ErrorDocument error-code action The error-code has to be a valid code such as 403 (Forbidden), 404 (Not Found), or 500 (Internal Server Error). The action can be either a URL (both local and external), or a message string enclosed in double quotes (that is, "). Example 15.34. Using the ErrorDocument directive ErrorDocument 403 "Access Denied"ErrorDocument 404 /404-not_found.html
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ErrorLog The ErrorLog directive allows you to specify a file to which the server errors are logged. It takes the following form: ErrorLog path The path refers to a log file, and can be either absolute, or relative to the directory that is specified by the ServerRoot directive (that is, /etc/httpd/ by default). The default option is logs/error_log Example 15.35. Using the ErrorLog directive
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ExtendedStatus The ExtendedStatus directive allows you to enable detailed server status information. It takes the following form: ExtendedStatus option Table 15.7. Available ExtendedStatus options | Option | Description |
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On | Enables generating the detailed server status. | Off | Disables generating the detailed server status. |
Example 15.36. Using the ExtendedStatus directive
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Group The Group directive allows you to specify the group under which the httpd service will run. It takes the following form: Group group The group has to be an existing UNIX group. The default option is apache. Note that Group is no longer supported inside <VirtualHost>, and has been replaced by the SuexecUserGroup directive. Example 15.37. Using the Group directive
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HeaderName The HeaderName directive allows you to specify a file to be prepended to the beginning of the server-generated directory listing. It takes the following form: HeaderName filename The filename is a name of the file to look for in the requested directory. By default, the server looks for HEADER.html. Example 15.38. Using the HeaderName directive
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HostnameLookups The HostnameLookups directive allows you to enable automatic resolving of IP addresses. It takes the following form: HostnameLookups option Table 15.8. Available HostnameLookups options | Option | Description |
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On | Enables resolving the IP address for each connection so that the hostname can be logged. However, this also adds a significant processing overhead. | Double | Enables performing the double-reverse DNS lookup. In comparison to the above option, this adds even more processing overhead. | Off | Disables resolving the IP address for each connection. |
Note that when the presence of hostnames is required in server log files, it is often possible to use one of the many log analyzer tools that perform the DNS lookups more efficiently. Example 15.39. Using the HostnameLookups directive
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Include The Include directive allows you to include other configuration files. It takes the following form: Include filename The filename can be an absolute path, a path relative to the directory specified by the ServerRoot directive, or a wildcard expression. All configuration files from the /etc/httpd/conf.d/ directory are loaded by default. Example 15.40. Using the Include directive
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IndexIgnore The IndexIgnore directive allows you to specify a list of file names to be omitted from the server-generated directory listings. It takes the following form: IndexIgnore filename . . . . . . The filename option can be either a full file name, or a wildcard expression. Example 15.41. Using the IndexIgnore directive IndexIgnore .??* *~ *# HEADER* README* RCS CVS *,v *,t
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IndexOptions The IndexOptions directive allows you to customize the behavior of server-generated directory listings. It takes the following form: IndexOptions option . . . . . . Table 15.9. Available directory listing options | Option | Description |
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Charset=encoding | Specifies the character set of a generated web page. The encoding has to be a valid character set such as UTF-8 or ISO-8859-2. | Type=content-type | Specifies the media type of a generated web page. The content-type has to be a valid MIME type such as text/html or text/plain. | DescriptionWidth=value | Specifies the width of the description column. The value can be either a number of characters, or an asterisk (that is, *) to adjust the width automatically. | FancyIndexing | Enables advanced features such as different icons for certain files or possibility to re-sort a directory listing by clicking on a column header. | FolderFirst | Enables listing directories first, always placing them above files. | HTMLTable | Enables the use of HTML tables for directory listings. | IconsAreLinks | Enables using the icons as links. | IconHeight=value | Specifies an icon height. The value is a number of pixels. | IconWidth=value | Specifies an icon width. The value is a number of pixels. | IgnoreCase | Enables sorting files and directories in a case-sensitive manner. | IgnoreClient | Disables accepting query variables from a client. | NameWidth=value | Specifies the width of the file name column. The value can be either a number of characters, or an asterisk (that is, *) to adjust the width automatically. | ScanHTMLTitles | Enables parsing the file for a description (that is, the title element) in case it is not provided by the AddDescription directive. | ShowForbidden | Enables listing the files with otherwise restricted access. | SuppressColumnSorting | Disables re-sorting a directory listing by clicking on a column header. | SuppressDescription | Disables reserving a space for file descriptions. | SuppressHTMLPreamble | Disables the use of standard HTML preamble when a file specified by the HeaderName directive is present. | SuppressIcon | Disables the use of icons in directory listings. | SuppressLastModified | Disables displaying the date of the last modification field in directory listings. | SuppressRules | Disables the use of horizontal lines in directory listings. | SuppressSize | Disables displaying the file size field in directory listings. | TrackModified | Enables returning the Last-Modified and ETag values in the HTTP header. | VersionSort | Enables sorting files that contain a version number in the expected manner. | XHTML | Enables the use of XHTML 1.0 instead of the default HTML 3.2. |
Example 15.42. Using the IndexOptions directive IndexOptions FancyIndexing VersionSort NameWidth=* HTMLTable Charset=UTF-8
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KeepAlive The KeepAlive directive allows you to enable persistent connections. It takes the following form: KeepAlive option Table 15.10. Available KeepAlive options | Option | Description |
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On | Enables the persistent connections. In this case, the server will accept more than one request per connection. | Off | Disables the keep-alive connections. |
Note that when the persistent connections are enabled, on a busy server, the number of child processes can increase rapidly and eventually reach the maximum limit, slowing down the server significantly. To reduce the risk, it is recommended that you set KeepAliveTimeout to a low number, and monitor the /var/log/httpd/logs/error_log log file carefully. Example 15.43. Using the KeepAlive directive
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KeepAliveTimeout The KeepAliveTimeout directive allows you to specify the amount of time to wait for another request before closing the connection. It takes the following form: KeepAliveTimeout time The time is specified in seconds. The default option is 15. Example 15.44. Using the KeepAliveTimeout directive
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LanguagePriority The LanguagePriority directive allows you to customize the precedence of languages. It takes the following form: LanguagePriority language . . . . . . The language has to be a valid MIME language such as cs, en, or fr. This directive is especially useful for web servers that serve content in multiple languages based on the client's language settings. Example 15.45. Using the LanguagePriority directive LanguagePriority sk cs en
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Listen The Listen directive allows you to specify IP addresses or ports to listen to. It takes the following form: Listen [ip-address:]port [protocol] The ip-address is optional and unless supplied, the server will accept incoming requests on a given port from all IP addresses. Since the protocol is determined automatically from the port number, it can be usually omitted. The default option is to listen to port 80. Note that if the server is configured to listen to a port under 1024, only superuser will be able to start the httpd service. Example 15.46. Using the Listen directive
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LoadModule The LoadModule directive allows you to load a Dynamic Shared Object ( DSO) module. It takes the following form: LoadModule name path The name has to be a valid identifier of the required module. The path refers to an existing module file, and must be relative to the directory in which the libraries are placed (that is, /usr/lib/httpd/ on 32-bit and /usr/lib64/httpd/ on 64-bit systems by default). Example 15.47. Using the LoadModule directive LoadModule php5_module modules/libphp5.so
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LogFormat The LogFormat directive allows you to specify a log file format. It takes the following form: LogFormat format name Table 15.11. Common LogFormat options | Option | Description |
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%b | Represents the size of the response in bytes. | %h | Represents the IP address or hostname of a remote client. | %l | Represents the remote log name if supplied. If not, a hyphen (that is, -) is used instead. | %r | Represents the first line of the request string as it came from the browser or client. | %s | Represents the status code. | %t | Represents the date and time of the request. | %u | If the authentication is required, it represents the remote user. If not, a hyphen (that is, -) is used instead. | %{field} | Represents the content of the HTTP header field. The common options include %{Referer} (the URL of the web page that referred the client to the server) and %{User-Agent} (the type of the web browser making the request). |
Example 15.48. Using the LogFormat directive LogFormat "%h %l %u %t \"%r\" %>s %b" common
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LogLevel The LogLevel directive allows you to customize the verbosity level of the error log. It takes the following form: LogLevel option Table 15.12. Available LogLevel options | Option | Description |
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emerg | Only the emergency situations when the server cannot perform its work are logged. | alert | All situations when an immediate action is required are logged. | crit | All critical conditions are logged. | error | All error messages are logged. | warn | All warning messages are logged. | notice | Even normal, but still significant situations are logged. | info | Various informational messages are logged. | debug | Various debugging messages are logged. |
Example 15.49. Using the LogLevel directive
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MaxKeepAliveRequests The MaxKeepAliveRequests directive allows you to specify the maximum number of requests for a persistent connection. It takes the following form: MaxKeepAliveRequests number A high number can improve the performance of the server. Note that using 0 allows unlimited number of requests. The default option is 100. Example 15.50. Using the MaxKeepAliveRequests option
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NameVirtualHost The NameVirtualHost directive allows you to specify the IP address and port number for a name-based virtual host. It takes the following form: NameVirtualHost ip-address[:port] The ip-address can be either a full IP address, or an asterisk (that is, *) representing all interfaces. Note that IPv6 addresses have to be enclosed in square brackets (that is, [ and ]). The port is optional. Name-based virtual hosting allows one Apache HTTP Server to serve different domains without using multiple IP addresses. Name-based virtual hosts only work with non-secure HTTP connections. If using virtual hosts with a secure server, use IP address-based virtual hosts instead. Example 15.51. Using the NameVirtualHost directive
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Options The Options directive allows you to specify which server features are available in a particular directory. It takes the following form: Options option . . . . . . Table 15.13. Available server features | Option | Description |
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ExecCGI | Enables the execution of CGI scripts. | FollowSymLinks | Enables following symbolic links in the directory. | Includes | Enables server-side includes. | IncludesNOEXEC | Enables server-side includes, but does not allow the execution of commands. | Indexes | Enables server-generated directory listings. | MultiViews | Enables content-negotiated "MultiViews". | SymLinksIfOwnerMatch | Enables following symbolic links in the directory when both the link and the target file have the same owner. | All | Enables all of the features above with the exception of MultiViews. | None | Disables all of the features above. |
Example 15.52. Using the Options directive Options Indexes FollowSymLinks
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Order The Order directive allows you to specify the order in which the Allow and Deny directives are evaluated. It takes the following form: Order option Table 15.14. Available Order options | Option | Description |
|---|
allow,deny | Allow directives are evaluated first. | deny,allow | Deny directives are evaluated first. |
Example 15.53. Using the Order directive
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PidFile The PidFile directive allows you to specify a file to which the process ID ( PID) of the server is stored. It takes the following form: PidFile path The path refers to a pid file, and can be either absolute, or relative to the directory that is specified by the ServerRoot directive (that is, /etc/httpd/ by default). The default option is run/httpd.pid. Example 15.54. Using the PidFile directive
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ProxyRequests The ProxyRequests directive allows you to enable forward proxy requests. It takes the following form: ProxyRequests option Table 15.15. Available ProxyRequests options | Option | Description |
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On | Enables forward proxy requests. | Off | Disables forward proxy requests. |
Example 15.55. Using the ProxyRequests directive
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ReadmeName The ReadmeName directive allows you to specify a file to be appended to the end of the server-generated directory listing. It takes the following form: ReadmeName filename The filename is a name of the file to look for in the requested directory. By default, the server looks for README.html. Example 15.56. Using the ReadmeName directive
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Redirect The Redirect directive allows you to redirect a client to another URL. It takes the following form: Redirect [status] path url The status is optional, and if provided, it has to be a valid keyword as described in Table 15.16, "Available status options". The path refers to the old location, and must be relative to the directory specified by the DocumentRoot directive (for example, /docs). The url refers to the current location of the content (for example, http://docs.example.com). Table 15.16. Available status options | Status | Description |
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permanent | Indicates that the requested resource has been moved permanently. The 301 (Moved Permanently) status code is returned to a client. | temp | Indicates that the requested resource has been moved only temporarily. The 302 (Found) status code is returned to a client. | seeother | Indicates that the requested resource has been replaced. The 303 (See Other) status code is returned to a client. | gone | Indicates that the requested resource has been removed permanently. The 410 (Gone) status is returned to a client. |
Note that for more advanced redirection techniques, you can use the mod_rewrite module that is part of the Apache HTTP Server installation. Example 15.57. Using the Redirect directive Redirect permanent /docs http://docs.example.com
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ScriptAlias The ScriptAlias directive allows you to specify the location of CGI scripts. It takes the following form: ScriptAlias url-path real-path The url-path must be relative to the directory specified by the DocumentRoot directive (for example, /cgi-bin/). The real-path is a full path to a file or directory in the local file system. This directive is typically followed by the Directory tag with additional permissions to access the target directory. By default, the /cgi-bin/ alias is created so that the scripts located in the /var/www/cgi-bin/ are accessible. The ScriptAlias directive is used for security reasons to prevent CGI scripts from being viewed as ordinary text documents. Example 15.58. Using the ScriptAlias directive ScriptAlias /cgi-bin/ /var/www/cgi-bin/<Directory "/var/www/cgi-bin"> AllowOverride None Options None Order allow,deny Allow from all</Directory>
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ServerAdmin The ServerAdmin directive allows you to specify the email address of the server administrator to be displayed in server-generated web pages. It takes the following form: ServerAdmin email The default option is root@localhost. This directive is commonly set to webmaster@hostname, where hostname is the address of the server. Once set, alias webmaster to the person responsible for the web server in /etc/aliases, and as superuser, run the newaliases command. Example 15.59. Using the ServerAdmin directive
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ServerName The ServerName directive allows you to specify the hostname and the port number of a web server. It takes the following form: ServerName hostname[:port] The hostname has to be a fully qualified domain name ( FQDN) of the server. The port is optional, but when supplied, it has to match the number specified by the Listen directive. When using this directive, make sure that the IP address and server name pair are included in the /etc/hosts file. Example 15.60. Using the ServerName directive ServerName penguin.example.com:80
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ServerRoot The ServerRoot directive allows you to specify the directory in which the server operates. It takes the following form: ServerRoot directory The directory must be a full path to an existing directory in the local file system. The default option is /etc/httpd/. Example 15.61. Using the ServerRoot directive
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ServerSignature The ServerSignature directive allows you to enable displaying information about the server on server-generated documents. It takes the following form: ServerSignature option Table 15.17. Available ServerSignature options | Option | Description |
|---|
On | Enables appending the server name and version to server-generated pages. | Off | Disables appending the server name and version to server-generated pages. | EMail | Enables appending the server name, version, and the email address of the system administrator as specified by the ServerAdmin directive to server-generated pages. |
Example 15.62. Using the ServerSignature directive
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ServerTokens The ServerTokens directive allows you to customize what information is included in the Server response header. It takes the following form: ServerTokens option Table 15.18. Available ServerTokens options | Option | Description |
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Prod | Includes the product name only (that is, Apache). | Major | Includes the product name and the major version of the server (for example, 2). | Minor | Includes the product name and the minor version of the server (for example, 2.2). | Min | Includes the product name and the minimal version of the server (for example, 2.2.15). | OS | Includes the product name, the minimal version of the server, and the type of the operating system it is running on (for example, Red Hat). | Full | Includes all the information above along with the list of loaded modules. |
Note that for security reasons, it is recommended to reveal as little information about the server as possible. Example 15.63. Using the ServerTokens directive
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SuexecUserGroup The SuexecUserGroup directive allows you to specify the user and group under which the CGI scripts will be run. It takes the following form: SuexecUserGroup user group The user has to be an existing user, and the group must be a valid UNIX group. For security reasons, the CGI scripts should not be run with root privileges. Note that in <VirtualHost>, SuexecUserGroup replaces the User and Group directives. Example 15.64. Using the SuexecUserGroup directive SuexecUserGroup apache apache
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Timeout The Timeout directive allows you to specify the amount of time to wait for an event before closing a connection. It takes the following form: Timeout time The time is specified in seconds. The default option is 60. Example 15.65. Using the Timeout directive
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TypesConfig The TypesConfig allows you to specify the location of the MIME types configuration file. It takes the following form: TypesConfig path The path refers to an existing MIME types configuration file, and can be either absolute, or relative to the directory that is specified by the ServerRoot directive (that is, /etc/httpd/ by default). The default option is /etc/mime.types. Note that instead of editing /etc/mime.types, the recommended way to add MIME type mapping to the Apache HTTP Server is to use the AddType directive. Example 15.66. Using the TypesConfig directive TypesConfig /etc/mime.types
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UseCanonicalName The UseCanonicalName allows you to specify the way the server refers to itself. It takes the following form: UseCanonicalName option Table 15.19. Available UseCanonicalName options | Option | Description |
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On | Enables the use of the name that is specified by the ServerName directive. | Off | Disables the use of the name that is specified by the ServerName directive. The hostname and port number provided by the requesting client are used instead. | DNS | Disables the use of the name that is specified by the ServerName directive. The hostname determined by a reverse DNS lookup is used instead. |
Example 15.67. Using the UseCanonicalName directive
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User The User directive allows you to specify the user under which the httpd service will run. It takes the following form: User user The user has to be an existing UNIX user. The default option is apache. For security reasons, the httpd service should not be run with root privileges. Note that User is no longer supported inside <VirtualHost>, and has been replaced by the SuexecUserGroup directive. Example 15.68. Using the User directive
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UserDir The UserDir directive allows you to enable serving content from users' home directories. It takes the following form: UserDir option The option can be either a name of the directory to look for in user's home directory (typically public_html), or a valid keyword as described in Table 15.20, "Available UserDir options". The default option is disabled. Table 15.20. Available UserDir options | Option | Description |
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enabled user . . . . . . | Enables serving content from home directories of given users. | disabled [user . . . . . . ] | Disables serving content from home directories, either for all users, or, if a space separated list of users is supplied, for given users only. |
In order for the web server to access the content, the permissions on relevant directories and files must be set correctly. Make sure that all users are able to access the home directories, and that they can access and read the content of the directory specified by the UserDir directive. For example: ~]# chmod a+x /home/username/~]# chmod a+rx /home/username/public_html/ All files in this directory must be set accordingly. Example 15.69. Using the UserDir directive
15.1.5.2. Common ssl.conf DirectivesThe Secure Sockets Layer ( SSL) directives allow you to customize the behavior of the Apache HTTP Secure Server, and in most cases, they are configured appropriately during the installation. Be careful when changing these settings, as incorrect configuration can lead to security vulnerabilities. The following directive is commonly used in /etc/httpd/conf.d/ssl.conf: -
SetEnvIf The SetEnvIf directive allows you to set environment variables based on the headers of incoming connections. It takes the following form: SetEnvIf option pattern [!]variable[=value] . . . . . . The option can be either a HTTP header field, a previously defined environment variable name, or a valid keyword as described in Table 15.21, "Available SetEnvIf options". The pattern is a regular expression. The variable is an environment variable that is set when the option matches the pattern. If the optional exclamation mark (that is, !) is present, the variable is removed instead of being set. Table 15.21. Available SetEnvIf options | Option | Description |
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Remote_Host | Refers to the client's hostname. | Remote_Addr | Refers to the client's IP address. | Server_Addr | Refers to the server's IP address. | Request_Method | Refers to the request method (for example, GET). | Request_Protocol | Refers to the protocol name and version (for example, HTTP/1.1). | Request_URI | Refers to the requested resource. |
The SetEnvIf directive is used to disable HTTP keepalives, and to allow SSL to close the connection without a closing notification from the client browser. This is necessary for certain web browsers that do not reliably shut down the SSL connection. Example 15.70. Using the SetEnvIf directive SetEnvIf User-Agent ".*MSIE.*" \ nokeepalive ssl-unclean-shutdown \ downgrade-1.0 force-response-1.0
Note that for the /etc/httpd/conf.d/ssl.conf file to be present, the mod_ssl needs to be installed. Refer to Section 15.1.8, "Setting Up an SSL Server" for more information on how to install and configure an SSL server. 15.1.5.3. Common Multi-Processing Module DirectivesThe Multi-Processing Module ( MPM) directives allow you to customize the behavior of a particular MPM specific server-pool. Since its characteristics differ depending on which MPM is used, the directives are embedded in IfModule. By default, the server-pool is defined for both the prefork and worker MPMs. The following MPM directives are commonly used in /etc/httpd/conf/httpd.conf: -
MaxClients The MaxClients directive allows you to specify the maximum number of simultaneously connected clients to process at one time. It takes the following form: MaxClients number A high number can improve the performance of the server, although it is not recommended to exceed 256 when using the prefork MPM. Example 15.71. Using the MaxClients directive
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MaxRequestsPerChild The MaxRequestsPerChild directive allows you to specify the maximum number of request a child process can serve before it dies. It takes the following form: MaxRequestsPerChild number Setting the number to 0 allows unlimited number of requests. The MaxRequestsPerChild directive is used to prevent long-lived processes from causing memory leaks. Example 15.72. Using the MaxRequestsPerChild directive
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MaxSpareServers The MaxSpareServers directive allows you to specify the maximum number of spare child processes. It takes the following form: MaxSpareServers number This directive is used by the prefork MPM only. Example 15.73. Using the MaxSpareServers directive
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MaxSpareThreads The MaxSpareThreads directive allows you to specify the maximum number of spare server threads. It takes the following form: MaxSpareThreads number The number must be greater than or equal to the sum of MinSpareThreads and ThreadsPerChild. This directive is used by the worker MPM only. Example 15.74. Using the MaxSpareThreads directive
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MinSpareServers The MinSpareServers directive allows you to specify the minimum number of spare child processes. It takes the following form: MinSpareServers number Note that a high number can create a heavy processing load on the server. This directive is used by the prefork MPM only. Example 15.75. Using the MinSpareServers directive
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MinSpareThreads The MinSpareThreads directive allows you to specify the minimum number of spare server threads. It takes the following form: MinSpareThreads number This directive is used by the worker MPM only. Example 15.76. Using the MinSpareThreads directive
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StartServers The StartServers directive allows you to specify the number of child processes to create when the service is started. It takes the following form: StartServers number Since the child processes are dynamically created and terminated according to the current traffic load, it is usually not necessary to change this value. Example 15.77. Using the StartServers directive
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ThreadsPerChild The ThreadsPerChild directive allows you to specify the number of threads a child process can create. It takes the following form: ThreadsPerChild number This directive is used by the worker MPM only. Example 15.78. Using the ThreadsPerChild directive
15.1.6. Working with ModulesBeing a modular application, the httpd service is distributed along with a number of Dynamic Shared Objects ( DSOs), which can be dynamically loaded or unloaded at runtime as necessary. By default, these modules are located in /usr/lib/httpd/modules/ on 32-bit and in /usr/lib64/httpd/modules/ on 64-bit systems. 15.1.6.1. Loading a ModuleTo load a particular DSO module, use the LoadModule directive as described in Section 15.1.5.1, "Common httpd.conf Directives". Note that modules provided by a separate package often have their own configuration file in the /etc/httpd/conf.d/ directory. Example 15.79. Loading the mod_ssl DSO LoadModule ssl_module modules/mod_ssl.so 15.1.6.2. Writing a ModuleIf you intend to create a new DSO module, make sure you have the httpd-devel package installed. To do so, type the following at a shell prompt: ~]# yum install httpd-devel This package contains the include files, the header files, and the APache eXtenSion (apxs) utility required to compile a module. Once written, you can build the module with the following command: ~]# apxs -i -a -c module_name.c If the build was successful, you should be able to load the module the same way as any other module that is distributed with the Apache HTTP Server. 15.1.7. Setting Up Virtual HostsThe Apache HTTP Server's built in virtual hosting allows the server to provide different information based on which IP address, hostname, or port is being requested. To create a name-based virtual host, find the virtual host container provided in /etc/httpd/conf/httpd.conf as an example, remove the hash sign (that is, #) from the beginning of each line, and customize the options according to your requirements as shown in Example 15.80, "Sample virtual host configuration". Example 15.80. Sample virtual host configuration NameVirtualHost penguin.example.com:80<VirtualHost penguin.example.com:80> ServerAdmin [email protected] DocumentRoot /www/docs/penguin.example.com ServerName penguin.example.com:80 ErrorLog logs/penguin.example.com-error_log CustomLog logs/penguin.example.com-access_log common</VirtualHost> Note that ServerName must be a valid DNS name assigned to the machine. The <VirtualHost> container is highly customizable, and accepts most of the directives available within the main server configuration. Directives that are not supported within this container include User and Group, which were replaced by SuexecUserGroup. If you configure a virtual host to listen on a non-default port, make sure you update the Listen directive in the global settings section of the /etc/httpd/conf/httpd.conf file accordingly. 15.1.8. Setting Up an SSL ServerSecure Sockets Layer ( SSL) is a cryptographic protocol that allows a server and a client to communicate securely. Along with its extended and improved version called Transport Layer Security ( TLS), it ensures both privacy and data integrity. The Apache HTTP Server in combination with mod_ssl, a module that uses the OpenSSL toolkit to provide the SSL/TLS support, is commonly referred to as the SSL server. Unlike a regular HTTP connection that can be read and possibly modified by anybody who is able to intercept it, the use of mod_ssl prevents any inspection or modification of the transmitted content. This section provides basic information on how to enable this module in the Apache HTTP Server configuration, and guides you through the process of generating private keys and self-signed certificates. 15.1.8.1. An Overview of Certificates and SecuritySecure communication is based on the use of keys. In conventional or symmetric cryptography, both ends of the transaction have the same key they can use to decode each other's transmissions. On the other hand, in public or asymmetric cryptography, two keys co-exist: a private key that is kept a secret, and a public key that is usually shared with the public. While the data encoded with the public key can only be decoded with the private key, data encoded with the private key can in turn only be decoded with the public key. To provide secure communications using SSL, an SSL server must use a digital certificate signed by a Certificate Authority ( CA). The certificate lists various attributes of the server (that is, the server hostname, the name of the company, its location, etc.), and the signature produced using the CA's private key. This signature ensures that a particular certificate authority has issued the certificate, and that the certificate has not been modified in any way. When a web browser establishes a new SSL connection, it checks the certificate provided by the web server. If the certificate does not have a signature from a trusted CA, or if the hostname listed in the certificate does not match the hostname used to establish the connection, it refuses to communicate with the server and usually presents a user with an appropriate error message. By default, most web browsers are configured to trust a set of widely used certificate authorities. Because of this, an appropriate CA should be chosen when setting up a secure server, so that target users can trust the connection, otherwise they will be presented with an error message, and will have to accept the certificate manually. Since encouraging users to override certificate errors can allow an attacker to intercept the connection, you should use a trusted CA whenever possible. For more information on this, see Table 15.22, "CA lists for most common web browsers". Table 15.22. CA lists for most common web browsers When setting up an SSL server, you need to generate a certificate request and a private key, and then send the certificate request, proof of the company's identity, and payment to a certificate authority. Once the CA verifies the certificate request and your identity, it will send you a signed certificate you can use with your server. Alternatively, you can create a self-signed certificate that does not contain a CA signature, and thus should be used for testing purposes only. 15.1.8.2. Enabling the mod_ssl ModuleIf you intend to set up an SSL server, make sure you have the mod_ssl (the mod_ssl module) and openssl (the OpenSSL toolkit) packages installed. To do so, type the following at a shell prompt: ~]# yum install mod_ssl openssl This will create the mod_ssl configuration file at /etc/httpd/conf.d/ssl.conf, which is included in the main Apache HTTP Server configuration file by default. For the module to be loaded, restart the httpd service as described in Section 15.1.4.3, "Restarting the Service". 15.1.8.3. Using an Existing Key and CertificateIf you have a previously created key and certificate, you can configure the SSL server to use these files instead of generating new ones. There are only two situations where this is not possible: You are changing the IP address or domain name. Certificates are issued for a particular IP address and domain name pair. If one of these values changes, the certificate becomes invalid. You have a certificate from VeriSign, and you are changing the server software. VeriSign, a widely used certificate authority, issues certificates for a particular software product, IP address, and domain name. Changing the software product renders the certificate invalid.
If you wish to use an existing key and certificate, move the relevant files to the /etc/pki/tls/private/ and /etc/pki/tls/certs/ directories respectively. You can do so by typing the following commands: ~]# mv key_file.key/etc/pki/tls/private/hostname.key~]# mv certificate.crt/etc/pki/tls/certs/hostname.crt Then add the following lines to the /etc/httpd/conf.d/ssl.conf configuration file: SSLCertificateFile /etc/pki/tls/certs/hostname.crtSSLCertificateKeyFile /etc/pki/tls/private/hostname.key Example 15.81. Using a key and certificate from the Red Hat Secure Web Server ~]# mv /etc/httpd/conf/httpsd.key /etc/pki/tls/private/penguin.example.com.key~]# mv /etc/httpd/conf/httpsd.crt /etc/pki/tls/certs/penguin.example.com.crt 15.1.8.4. Generating a New Key and CertificateIn order to generate a new key and certificate pair, you must to have the crypto-utils package installed in your system. You can install it by typing the following at a shell prompt: ~]# yum install crypto-utils This package provides a set of tools to generate and manage SSL certificates and private keys, and includes genkey, the Red Hat Keypair Generation utility that will guide you through the key generation process. If the server already has a valid certificate and you are replacing it with a new one, specify a different serial number. This ensures that client browsers are notified of this change, update to this new certificate as expected, and do not fail to access the page. To create a new certificate with a custom serial number, use the following command instead of genkey: ~]# openssl req -x509 -new -set_serial number -key hostname.key -out hostname.crt If there already is a key file for a particular hostname in your system, genkey will refuse to start. In this case, remove the existing file using the following command: ~]# rm /etc/pki/tls/private/hostname.key To run the utility, use the genkey command followed by the appropriate hostname (for example, penguin.example.com): ~]# genkey hostname To complete the key and certificate creation, take the following steps: Review the target locations in which the key and certificate will be stored.
Use the Tab key to select the Next button, and press Enter to proceed to the next screen. Using the Up and down arrow keys, select the suitable key size. Note that while the large key increases the security, it also increases the response time of your server. Because of this, the recommended option is 1024 bits.
Once finished, use the Tab key to select the Next button, and press Enter to initiate the random bits generation process. Depending on the selected key size, this may take some time. Decide whether you wish to send a certificate request to a certificate authority.
Use the Tab key to select Yes to compose a certificate request, or No to generate a self-signed certificate. Then press Enter to confirm your choice. Using the Spacebar key, enable ([*]) or disable ([ ]) the encryption of the private key.
Use the Tab key to select the Next button, and press Enter to proceed to the next screen. If you have enabled the private key encryption, enter an adequate passphrase. Note that for security reasons, it is not displayed as you type, and it must be at least five characters long.
Use the Tab key to select the Next button, and press Enter to proceed to the next screen. Entering the correct passphrase is required in order for the server to start. If you lose it, you will need to generate a new key and certificate. Customize the certificate details.
Use the Tab key to select the Next button, and press Enter to finish the key generation. If you have previously enabled the certificate request generation, you will be prompted to send it to a certificate authority.
Press Enter to return to a shell prompt.
Once generated, add the key and certificate locations to the /etc/httpd/conf.d/ssl.conf configuration file: SSLCertificateFile /etc/pki/tls/certs/hostname.crtSSLCertificateKeyFile /etc/pki/tls/private/hostname.key 15.1.9. Additional ResourcesTo learn more about the Apache HTTP Server, refer to the following resources. 15.1.9.1. Installed Documentation- http://localhost/manual/
The official documentation for the Apache HTTP Server with the full description of its directives and available modules. Note that in order to access this documentation, you must have the httpd-manual package installed, and the web server must be running. -
man httpd The manual page for the httpd service containing the complete list of its command line options. -
man genkey The manual page for genkey containing the full documentation on its usage.
15.1.9.2. Useful Websites- http://httpd.apache.org/
The official website for the Apache HTTP Server with documentation on all the directives and default modules. - http://www.modssl.org/
The official website for the mod_ssl module. - http://www.openssl.org/
The OpenSSL home page containing further documentation, frequently asked questions, links to the mailing lists, and other useful resources.
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