Apache HTTP Server Version 2.5
Description: | Group authorizations based on host (name or IP address) |
---|---|
Status: | Extension |
Module Identifier: | access_compat_module |
Source File: | mod_access_compat.c |
Compatibility: | Available in Apache HTTP Server 2.3 as a compatibility module with
previous versions of Apache httpd 2.x. The directives provided by this module
have been deprecated by the new authz refactoring. Please see
mod_authz_host |
The directives provided by mod_access_compat
are
used in <Directory>
,
<Files>
, and
<Location>
sections
as well as .htaccess
files to control access to particular parts of the server.
Access can be controlled based on the client hostname, IP address, or
other characteristics of the client request, as captured in environment variables. The Allow
and Deny
directives are used to
specify which clients are or are not allowed access to the server,
while the Order
directive sets the default access state, and configures how the
Allow
and Deny
directives interact with each
other.
Both host-based access restrictions and password-based
authentication may be implemented simultaneously. In that case,
the Satisfy
directive is used
to determine how the two sets of restrictions interact.
The directives provided by mod_access_compat
have
been deprecated by the new authz refactoring. Please see
mod_authz_host
.
In general, access restriction directives apply to all
access methods (GET
, PUT
,
POST
, etc). This is the desired behavior in most
cases. However, it is possible to restrict some methods, while
leaving other methods unrestricted, by enclosing the directives
in a <Limit>
section.
When any directive provided by this module is used in a new configuration section, no directives provided by this module are inherited from previous configuration sections.
Description: | Controls which hosts can access an area of the server |
---|---|
Syntax: | Allow from all|host|env=[!]env-variable
[host|env=[!]env-variable] ... |
Context: | directory, .htaccess |
Override: | Limit |
Status: | Extension |
Module: | mod_access_compat |
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
Deny
and 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:
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.
Allow from 10.1.2.3 Allow from 192.168.1.104 192.168.1.205
An IP address of a host allowed access
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.
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.
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 environment variable. When Allow from
env=env-variable
is specified, then the request is
allowed access if the environment variable env-variable
exists. When Allow from env=!env-variable
is
specified, then the request is allowed access if the environment
variable env-variable doesn't exist.
The server provides the ability to set environment
variables in a flexible way based on characteristics of the client
request using the directives provided by
mod_setenvif
. Therefore, this directive can be
used to allow access based on such factors as the clients
User-Agent
(browser type), Referer
, or
other HTTP request header fields.
SetEnvIf User-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 user-agent string beginning
with KnockKnock/2.0
will be allowed access, and all
others will be denied.
When any directive provided by this module is used in a new configuration section, no directives provided by this module are inherited from previous configuration sections.
Description: | Controls which hosts are denied access to the server |
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Syntax: | Deny from all|host|env=[!]env-variable
[host|env=[!]env-variable] ... |
Context: | directory, .htaccess |
Override: | Limit |
Status: | Extension |
Module: | mod_access_compat |
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.
Description: | Controls the default access state and the order in which
Allow and Deny are
evaluated. |
---|---|
Syntax: | Order ordering |
Default: | Order Deny,Allow |
Context: | directory, .htaccess |
Override: | Limit |
Status: | Extension |
Module: | mod_access_compat |
The Order
directive, along with the
Allow
and
Deny
directives,
controls a three-pass access control system. The first pass
processes either all Allow
or all Deny
directives, as specified
by the Order
directive. The second pass parses the rest of the directives
(Deny
or
Allow
). The third
pass applies to all requests which do not match either of the first
two.
Note that all Allow
and Deny
directives are
processed, unlike a typical firewall, where only the first match is
used. The last match is effective (also unlike a typical firewall).
Additionally, the order in which lines appear in the configuration
files is not significant -- all Allow
lines are processed as
one group, all Deny
lines are considered as
another, and the default state is considered by itself.
Ordering is one of:
Allow,Deny
Allow
directives are
evaluated; at least one must match, or the request is rejected.
Next, all Deny
directives are evaluated. If any matches, the request is rejected.
Last, any requests which do not match an Allow
or a Deny
directive are denied
by default.Deny,Allow
Deny
directives are
evaluated; if any match, the request is denied
unless it also matches an Allow
directive. Any
requests which do not match any Allow
or Deny
directives are
permitted.Mutual-failure
Order
Allow,Deny
and is deprecated in its favor.Keywords may only be separated by a comma; no whitespace is allowed between them.
Match | Allow,Deny result | Deny,Allow result |
---|---|---|
Match Allow only | Request allowed | Request allowed |
Match Deny only | Request denied | Request denied |
No match | Default to second directive: Denied | Default to second directive: Allowed |
Match both Allow & Deny | Final match controls: Denied | Final match controls: Allowed |
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 Allow
and 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
Allow
or Deny
directive occurring in a
<Location>
section will
always be evaluated after an Allow
or Deny
directive occurring in a
<Directory>
section or
.htaccess
file, regardless of the setting of the
Order
directive. For details on the merging
of configuration sections, see the documentation on How Directory, Location and Files sections
work.
When any directive provided by this module is used in a new configuration section, no directives provided by this module are inherited from previous configuration sections.
Description: | Interaction between host-level access control and user authentication |
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Syntax: | Satisfy Any|All |
Default: | Satisfy All |
Context: | directory, .htaccess |
Override: | AuthConfig |
Status: | Extension |
Module: | mod_access_compat |
Compatibility: | Influenced by <Limit> and <LimitExcept> in version 2.0.51 and
later |
Access policy if both Allow
and 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
username/password and client host address. In this case
the default behavior (All
) is to require that the client
passes the address access restriction and enters a valid
username and password. With the Any
option the client will be
granted access if they either pass the host restriction or enter a
valid username and password. This can be used to password restrict
an area, but to let clients from particular addresses in without
prompting for a password.
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 password, you could use a configuration similar to the following:
Require valid-user 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-user </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 <Limit>
and <LimitExcept>
sections.
When any directive provided by this module is used in a new configuration section, no directives provided by this module are inherited from previous configuration sections.