Apache Module mod_access_compat 48517

Allow Directive 491o4x

The Allow directive affects which hosts can access an area of the server. Access can be controlled by hostname, IP address, IP address range, or by other characteristics of the client request captured in environment variables.

The first argument to this directive is always from. The subsequent arguments can take three different forms. If Allow from all is specified, then all hosts are allowed access, subject to the configuration of the Order directives as discussed below. To allow only particular hosts or groups of hosts to access the server, the host can be specified in any of the following formats:

A (partial) domain-name

Allow from example.org
Allow from .net example.edu

Hosts whose names match, or end in, this string are allowed access. Only complete components are matched, so the above example will match foo.example.org but it will not match fooexample.org. This configuration will cause Apache httpd to perform a double DNS lookup on the client IP address, regardless of the setting of the HostnameLookups directive. It will do a reverse DNS lookup on the IP address to find the associated hostname, and then do a forward lookup on the hostname to assure that it matches the original IP address. Only if the forward and reverse DNS are consistent and the hostname matches will access be allowed.

A full IP address

Allow from 10.1.2.3
Allow from 192.168.1.104 192.168.1.205

An IP address of a host allowed access

A partial IP address

Allow from 10.1
Allow from 10 172.20 192.168.2

The first 1 to 3 bytes of an IP address, for subnet restriction.

A network/netmask pair

Allow from 10.1.0.0/255.255.0.0

A network a.b.c.d, and a netmask w.x.y.z. For more fine-grained subnet restriction.

A network/nnn CIDR specification

Allow from 10.1.0.0/16

Similar to the previous case, except the netmask consists of nnn high-order 1 bits.

Note that the last three examples above match exactly the same set of hosts.

IPv6 addresses and IPv6 subnets can be specified as shown below:

Allow from 2001:db8::a00:20ff:fea7:ccea
Allow from 2001:db8::a00:20ff:fea7:ccea/10

The third format of the arguments to the Allow directive allows access to the server to be controlled based on the existence of an mod_setenvif. Therefore, this directive can be used to allow access based on such factors as the clients -Agent (browser type), Referer, or other HTTP request header fields.

SetEnvIf -Agent ^KnockKnock/2\.0 let_me_in
<Directory "/docroot">
    Order Deny,Allow
    Deny from all
    Allow from env=let_me_in
</Directory>

In this case, browsers with a -agent string beginning with KnockKnock/2.0 will be allowed access, and all others will be denied.

Deny Directive zim

This directive allows access to the server to be restricted based on hostname, IP address, or environment variables. The arguments for the Deny directive are identical to the arguments for the Allow directive.

Order Directive 4m6k3r

The Order directive, along with the Allow). The third applies to all requests which do not match either of the first two.

Note that all Deny lines are considered as another, and the default state is considered by itself.

Ordering is one of:

Allow,Deny

First, all Deny directive are denied by default.

Deny,Allow

First, all Deny directives are permitted.

Mutual-failure

This order has the same effect as Order Allow,Deny and is deprecated in its favor.

Keywords may only be separated by a comma; no whitespace is allowed between them.

In the following example, all hosts in the example.org domain are allowed access; all other hosts are denied access.

Order Deny,Allow
Deny from all
Allow from example.org

In the next example, all hosts in the example.org domain are allowed access, except for the hosts which are in the foo.example.org subdomain, who are denied access. All hosts not in the example.org domain are denied access because the default state is to Deny access to the server.

Order Allow,Deny
Allow from example.org
Deny from foo.example.org

On the other hand, if the Order in the last example is changed to Deny,Allow, all hosts will be allowed access. This happens because, regardless of the actual ordering of the directives in the configuration file, the Allow from example.org will be evaluated last and will override the Deny from foo.example.org. All hosts not in the example.org domain will also be allowed access because the default state is Allow.

The presence of an Order directive can affect access to a part of the server even in the absence of accompanying Deny directives because of its effect on the default access state. For example,

<Directory "/www">
    Order Allow,Deny
</Directory>

will Deny all access to the /www directory because the default access state is set to Deny.

The Order directive controls the order of access directive processing only within each phase of the server's configuration processing. This implies, for example, that an How Directory, Location and Files sections work.

Satisfy Directive 1ot62

Access policy if both Require used. The parameter can be either All or Any. This directive is only useful if access to a particular area is being restricted by both name/ and client host address. In this case the default behavior (All) is to require that the client es the address access restriction and enters a valid name and . With the Any option the client will be granted access if they either the host restriction or enter a valid name and . This can be used to restrict an area, but to let clients from particular addresses in without prompting for a .

For example, if you wanted to let people on your network have unrestricted access to a portion of your website, but require that people outside of your network provide a , you could use a configuration similar to the following:

Require valid-
Allow from 192.168.1
Satisfy Any

Another frequent use of the Satisfy directive is to relax access restrictions for a subdirectory:

<Directory "/var/www/private">
    Require valid-
</Directory>

<Directory "/var/www/private/public">
    Allow from all
    Satisfy Any
</Directory>

In the above example, authentication will be required for the /var/www/private directory, but will not be required for the /var/www/private/public directory.

Since version 2.0.51 Satisfy directives can be restricted to particular methods by <LimitExcept> sections.

See also 27136x

• Allow
• Require