The RewriteOptions directive sets some special options for the current per-server or per-directory configuration. The Option string can currently only be one of the following:

Inherit

This forces the current configuration to inherit the configuration of the parent. In per-virtual-server context, this means that the maps, conditions and rules of the main server are inherited. In per-directory context this means that conditions and rules of the parent directory's .htaccess configuration or <Directory> sections are inherited. The inherited rules are virtually copied to the section where this directive is being used. If used in combination with local rules, the inherited rules are copied behind the local rules. The position of this directive - below or above of local rules - has no influence on this behavior. If local rules forced the rewriting to stop, the inherited rules won't be processed.

Rules inherited from the parent scope are applied after rules specified in the child scope.

InheritBefore

Like Inherit above, but the rules from the parent scope are applied before rules specified in the child scope.
Available in Apache HTTP Server 2.3.10 and later.

InheritDown

If this option is enabled, all child configurations will inherit the configuration of the current configuration. It is equivalent to specifying RewriteOptions Inherit in all child configurations. See the Inherit option for more details on how the parent-child relationships are handled.
Available in Apache HTTP Server 2.4.8 and later.

InheritDownBefore

Like InheritDown above, but the rules from the current scope are applied before rules specified in any child's scope.
Available in Apache HTTP Server 2.4.8 and later.

IgnoreInherit

This option forces the current and child configurations to ignore all rules that would be inherited from a parent specifying InheritDown or InheritDownBefore .
Available in Apache HTTP Server 2.4.8 and later.

AllowNoSlash

By default, mod_rewrite will ignore URLs that map to a directory on disk but lack a trailing slash, in the expectation that the mod_dir module will issue the client with a redirect to the canonical URL with a trailing slash.

When the DirectorySlash directive is set to off, the AllowNoSlash option can be enabled to ensure that rewrite rules are no longer ignored. This option makes it possible to apply rewrite rules within .htaccess files that match the directory without a trailing slash, if so desired.
Available in Apache HTTP Server 2.4.0 and later.

AllowAnyURI

When RewriteRule is used in VirtualHost or server context with version 2.2.22 or later of httpd, mod_rewrite will only process the rewrite rules if the request URI is a URL-path. This avoids some security issues where particular rules could allow "surprising" pattern expansions (see CVE-2011-3368 and CVE-2011-4317). To lift the restriction on matching a URL-path, the AllowAnyURI option can be enabled, and mod_rewrite will apply the rule set to any request URI string, regardless of whether that string matches the URL-path grammar required by the HTTP specification.
Available in Apache HTTP Server 2.4.3 and later.

Security Warning

Enabling this option will make the server vulnerable to security issues if used with rewrite rules which are not carefully authored. It is strongly recommended that this option is not used. In particular, beware of input strings containing the ' @ ' character which could change the interpretation of the transformed URI, as per the above CVE names.

MergeBase

With this option, the value of RewriteBase is copied from where it's explicitly defined into any sub-directory or sub-location that doesn't define its own RewriteBase . This was the default behavior in 2.4.0 through 2.4.3, and the flag to restore it is available Apache HTTP Server 2.4.4 and later.

IgnoreContextInfo

When a relative substitution is made in directory (htaccess) context and RewriteBase has not been set, this module uses some extended URL and filesystem context information to change the relative substitution back into a URL. Modules such as mod_userdir and mod_alias supply this extended context info. Available in 2.4.16 and later.

LegacyPrefixDocRoot

Prior to 2.4.26, if a substitution was an absolute URL that matched the current virtual host, the URL might first be reduced to a URL-path and then later reduced to a local path. Since the URL can be reduced to a local path, the path should be prefixed with the document root. This prevents a file such as /tmp/myfile from being accessed when a request is made to http://host/file/myfile with the following RewriteRule .

RewriteRule /file/(.*) http://localhost/tmp/$1

This option allows the old behavior to be used where the document root is not prefixed to a local path that was reduced from a URL. Available in 2.4.26 and later.