Apache HTTP Server Version 2.5
Description: | Replaces the original peer IP address for the connection with the client IP address list presented by a proxies or a load balancer via the request headers. |
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Status: | Base |
Module Identifier: | remoteip_module |
Source File: | mod_remoteip.c |
This module is used to treat the client which initiated the request as the originating client as identified by httpd for the purposes of authorization and logging, even where that client is behind a load balancer, front end server, or proxy server.
The module overrides the peer IP address for the connection
with the client IP address reported in the request header configured
with the RemoteIPHeader
directive.
Once replaced as instructed, this overridden client IP address is
then used for the mod_authz_host
<Require ip>
feature, is reported by mod_status
, and is recorded by
mod_log_config
%a
and core
%a
format strings. The underlying peer IP of the connection
is available in the %{c}a
format string.
Apache by default identifies the client with the connection's peer_ip value, and the connection remote_host and remote_logname are derived from this value. These fields play a role in authentication, authorization and logging and other purposes by other loadable modules.
mod_remoteip overrides the peer IP of the connection with the advertised client IP as provided by a proxy or load balancer, for the duration of the request. A load balancer might establish a long lived keepalive connection with the server, and each request will have the correct client IP, even though the underlying peer IP address of the load balancer remains unchanged.
When multiple, comma delimited client IP addresses are listed in the header value, they are processed in Right-to-Left order. Processing halts when a given client IP address is not trusted to present the preceding IP address. The header field is updated to this remaining list of unconfirmed IP addresses, or if all IP addresses were trusted, this header is removed from the request altogether.
In overriding the client IP, the module stores the list of intermediate
hosts in a remoteip-proxy-ip-list note, which mod_log_config
can record using the %{remoteip-proxy-ip-list}n
format token.
If the administrator needs to store this as an additional header, this
same value can also be recording as a header using the directive
RemoteIPProxiesHeader
.
RemoteIPInternalProxy
internal (intranet) proxies are registered.Description: | Declare the header field which should be parsed for client IP addresses |
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Syntax: | RemoteIPHeader header-field |
Context: | server config, virtual host |
Status: | Base |
Module: | mod_remoteip |
The RemoteIPHeader
directive triggers
mod_remoteip
to treat the value of the specified
header-field header as the client IP address, or list
of intermediate client IP addresses, subject to further configuration
of the RemoteIPInternalProxy
and
RemoteIPTrustedProxy
directives. Unless these
other directives are used, mod_remoteip
will trust all
hosts presenting a RemoteIPHeader
IP value.
RemoteIPHeader X-Client-IP
RemoteIPHeader X-Forwarded-For
Description: | Declare client intranet IP addresses trusted to present the RemoteIPHeader value |
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Syntax: | RemoteIPInternalProxy proxy-ip|proxy-ip/subnet|hostname ... |
Context: | server config, virtual host |
Status: | Base |
Module: | mod_remoteip |
The RemoteIPInternalProxy
directive adds one
or more addresses (or address blocks) to trust as presenting a valid
RemoteIPHeader value of the client IP. Unlike the
RemoteIPTrustedProxy
directive, any IP address
presented in this header, including private intranet addresses, are
trusted when passed from these proxies.
RemoteIPHeader X-Client-IP
RemoteIPTrustedProxy 10.0.2.0/24
RemoteIPTrustedProxy gateway.localdomain
Description: | Declare client intranet IP addresses trusted to present the RemoteIPHeader value |
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Syntax: | RemoteIPInternalProxyList filename |
Context: | server config, virtual host |
Status: | Base |
Module: | mod_remoteip |
The RemoteIPInternalProxyList
directive specifies
a file parsed at startup, and builds a list of addresses (or address blocks)
to trust as presenting a valid RemoteIPHeader value of the client IP.
The '#
' hash character designates a comment line, otherwise
each whitespace or newline separated entry is processed identically to
the RemoteIPInternalProxy
directive.
RemoteIPHeader X-Client-IP
RemoteIPTrustedProxyList conf/trusted-proxies.lst
# Our internally trusted proxies;
10.0.2.0/24 #Everyone in the testing group
gateway.localdomain #The front end balancer
Description: | Declare the header field which will record all intermediate IP addresses |
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Syntax: | RemoteIPProxiesHeader HeaderFieldName |
Context: | server config, virtual host |
Status: | Base |
Module: | mod_remoteip |
The RemoteIPProxiesHeader
directive specifies
a header into which mod_remoteip
will collect a list of
all of the intermediate client IP addresses trusted to resolve the client
IP of the request. Note that intermediate
RemoteIPTrustedProxy
addresses are recorded in
this header, while any intermediate
RemoteIPInternalProxy
addresses are discarded.
RemoteIPHeader X-Forwarded-For
RemoteIPProxiesHeader X-Forwarded-By
Description: | Declare client intranet IP addresses trusted to present the RemoteIPHeader value |
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Syntax: | RemoteIPTrustedProxy proxy-ip|proxy-ip/subnet|hostname ... |
Context: | server config, virtual host |
Status: | Base |
Module: | mod_remoteip |
The RemoteIPTrustedProxy
directive adds one
or more addresses (or address blocks) to trust as presenting a valid
RemoteIPHeader value of the client IP. Unlike the
RemoteIPInternalProxy
directive, any intranet
or private IP address reported by such proxies, including the 10/8, 172.16/12,
192.168/16, 169.254/16 and 127/8 blocks (or outside of the IPv6 public
2000::/3 block) are not trusted as the client IP, and are left in the
RemoteIPHeader
header's value.
RemoteIPHeader X-Forwarded-For
RemoteIPTrustedProxy 10.0.2.16/28
RemoteIPTrustedProxy proxy.example.com
Description: | Declare client intranet IP addresses trusted to present the RemoteIPHeader value |
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Syntax: | RemoteIPTrustedProxyList filename |
Context: | server config, virtual host |
Status: | Base |
Module: | mod_remoteip |
The RemoteIPTrustedProxyList
directive specifies
a file parsed at startup, and builds a list of addresses (or address blocks)
to trust as presenting a valid RemoteIPHeader value of the client IP.
The '#
' hash character designates a comment line, otherwise
each whitespace or newline seperated entry is processed identically to
the RemoteIPTrustedProxy
directive.
RemoteIPHeader X-Forwarded-For
RemoteIPTrustedProxyList conf/trusted-proxies.lst
# Identified external proxies;
192.0.2.16/28 #wap phone group of proxies
proxy.isp.example.com #some well known ISP