Apache Module mod_authz_host
Description: | Group authorizations based on host (name or IP address) |
---|---|
Status: | Base |
ModuleIdentifier: | authz_host_module |
SourceFile: | mod_authz_host.c |
Compatibility: | The forward-dns provider was addded in 2.4.19 |
Summary
The authorization providers implemented by mod_authz_host
are registered using the Require
directive. The directive can be referenced within a <Directory>
, <Files>
, or <Location>
section as well as .htaccess
files to control access to particular parts of the server. Access can be controlled based on the client hostname or IP address.
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.
The Require Directives
Apache's Require
directive is used during the authorization phase to ensure that a user is allowed or denied access to a resource. mod_authz_host extends the authorization types with ip
, host
, forward-dns
and local
. Other authorization types may also be used but may require that additional authorization modules be loaded.
These authorization providers affect which hosts can access an area of the server. Access can be controlled by hostname, IP Address, or IP Address range.
Since v2.4.8, expressions are supported within the host require directives.
Require ip
The ip
provider allows access to the server to be controlled based on the IP address of the remote client. When Require ip ip-address
is specified, then the request is allowed access if the IP address matches.
A full IP address:
Require ip 10.1.2.3 Require ip 192.168.1.104 192.168.1.205
An IP address of a host allowed access
A partial IP address:
Require ip 10.1 Require ip 10 172.20 192.168.2
The first 1 to 3 bytes of an IP address, for subnet restriction.
A network/netmask pair:
Require ip 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:
Require ip 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:
Require ip 2001:db8::a00:20ff:fea7:ccea Require ip 2001:db8:1:1::a Require ip 2001:db8:2:1::/64 Require ip 2001:db8:3::/48
Note: As the IP addresses are parsed on startup, expressions are not evaluated at request time.
Require host
The host
provider allows access to the server to be controlled based on the host name of the remote client. When Require host host-name
is specified, then the request is allowed access if the host name matches.
A (partial) domain-name
Require host example.org Require host .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 to perform a double reverse 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.
Require forward-dns
The forward-dns
provider allows access to the server to be controlled based on simple host names. When Require forward-dns host-name
is specified, all IP addresses corresponding to host-name
are allowed access.
In contrast to the host
provider, this provider does not rely on reverse DNS lookups: it simply queries the DNS for the host name and allows a client if its IP matches. As a consequence, it will only work with host names, not domain names. However, as the reverse DNS is not used, it will work with clients which use a dynamic DNS service.
Require forward-dns bla.example.org
A client the IP of which is resolved from the name bla.example.org
will be granted access.
The forward-dns
provider was added in 2.4.19.
Require local
The local
provider allows access to the server if any of the following conditions is true:
- the client address matches 127.0.0.0/8
- the client address is ::1
- both the client and the server address of the connection are the same
This allows a convenient way to match connections that originate from the local host:
Require local
Security Note
If you are proxying content to your server, you need to be aware that the client address will be the address of your proxy server, not the address of the client, and so using the Require
directive in this context may not do what you mean. See mod_remoteip
for one possible solution to this problem.
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