Further clarify the naming of the entity that directly connects to us by

      <li>Modules that load other modules later than the EXEC_ON_READ config

          reading stage need to call ap_reserve_module_slots() or

          ap_reserve_module_slots_directive() in their pre_config hook.</li>

      <li>The client IP address per request can now be specified independently

          of the peer IP address of the connection for the benefit of load

          balancers</li>

      <li>The useragent IP address per request can now be specified

          independently of the client IP address of the connection for

          the benefit of load balancers</li>

    </ul>

  </section>

      <dd>This has been renamed to ap_unixd_config.</dd>

      <dt><code>conn_rec->remote_ip and conn_rec->remote_addr</code></dt>

      <dd>In order to distinguish between the peer IP address of the

      connection, and the client IP address of the request potentially

      <dd>In order to distinguish between the client IP address of the

      connection, and the useragent IP address of the request potentially

      overridden by a load balancer or proxy, the above variables have

      been renamed. If a module makes reference to either of the above

      variables, they need to be replaced with one of the following two

        separated from the server by a transparent load balancer or

        proxy, use request_rec->useragent_ip and

        request_rec->useragent_addr.</li>

        <li>When you require the IP address of the peer that is

        connected directly to the server, which might be the client or

        <li>When you require the IP address of the client that is

        connected directly to the server, which might be the useragent or

        might be the load balancer or proxy itself, use

        conn_rec->peer_ip and conn_rec->peer_addr.</li>

        conn_rec->client_ip and conn_rec->client_addr.</li>

      </ul>

      </dd>

    </dl>

<modulesynopsis metafile="mod_remoteip.xml.meta">

<name>mod_remoteip</name>

<description>Replaces the original peer IP address for the connection

with the client IP address list presented by a proxies or a load balancer

<description>Replaces the original client IP address for the connection

with the useragent IP address list presented by a proxies or a load balancer

via the request headers.

</description>

<identifier>remoteip_module</identifier>

<summary>

    <p>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

    <p>This module is used to treat the useragent which initiated the

    request as the originating useragent as identified by httpd for the

    purposes of authorization and logging, even where that useragent is

    behind a load balancer, front end server, or proxy server.</p>

    <p>The module overrides the peer IP address for the connection

    with the client IP address reported in the request header configured

    <p>The module overrides the client IP address for the connection

    with the useragent IP address reported in the request header configured

    with the <directive>RemoteIPHeader</directive> directive.</p>

    <p>Once replaced as instructed, this overridden client IP address is

    <p>Once replaced as instructed, this overridden useragent IP address is

    then used for the <module>mod_authz_host</module>

    <directive module="mod_authz_host" type="section">Require ip</directive>

    feature, is reported by <module>mod_status</module>, and is recorded by

    <module>mod_log_config</module> <code>%a</code> and <module>core</module>

    <code>%a</code> format strings. The underlying peer IP of the connection

    <code>%a</code> format strings. The underlying client IP of the connection

    is available in the <code>%{c}a</code> format string.</p>

    <note type="warning">It is critical to only enable this behavior from

    intermediate hosts (proxies, etc) which are trusted by this server, since

    it is trivial for the remote client to impersonate another client.</note>

    it is trivial for the remote useragent to impersonate another

    useragent.</note>

</summary>

<seealso><module>mod_authz_host</module></seealso>

<section id="processing"><title>Remote IP Processing</title>

    <p>Apache by default identifies the client with the connection's

    peer_ip value, and the connection remote_host and remote_logname are

    <p>Apache by default identifies the useragent with the connection's

    client_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.</p>

    <p>mod_remoteip overrides the peer IP of the connection with the

    advertised client IP as provided by a proxy or load balancer, for

    <p>mod_remoteip overrides the client IP of the connection with the

    advertised useragent 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

    have the correct useragent IP, even though the underlying client IP

    address of the load balancer remains unchanged.</p>

    <p>When multiple, comma delimited client IP addresses are listed in the

    <p>When multiple, comma delimited useragent 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

    halts when a given useragent 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.</p>

<directivesynopsis>

<name>RemoteIPHeader</name>

<description>Declare the header field which should be parsed for client IP addresses</description>

<description>Declare the header field which should be parsed for useragent IP addresses</description>

<syntax>RemoteIPHeader <var>header-field</var></syntax>

<contextlist><context>server config</context><context>virtual host</context></contextlist>

<usage>

    <p>The <directive>RemoteIPHeader</directive> directive triggers

    <module>mod_remoteip</module> to treat the value of the specified

    <var>header-field</var> header as the client IP address, or list

    of intermediate client IP addresses, subject to further configuration

    <var>header-field</var> header as the useragent IP address, or list

    of intermediate useragent IP addresses, subject to further configuration

    of the <directive>RemoteIPInternalProxy</directive> and

    <directive>RemoteIPTrustedProxy</directive> directives.  Unless these

    other directives are used, <module>mod_remoteip</module> will trust all

<usage>

    <p>The <directive>RemoteIPInternalProxy</directive> directive adds one

    or more addresses (or address blocks) to trust as presenting a valid

    RemoteIPHeader value of the client IP.  Unlike the

    RemoteIPHeader value of the useragent IP.  Unlike the

    <directive>RemoteIPTrustedProxy</directive> directive, any IP address

    presented in this header, including private intranet addresses, are

    trusted when passed from these proxies.</p>

<usage>

    <p>The <directive>RemoteIPInternalProxyList</directive> 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.</p>

    to trust as presenting a valid RemoteIPHeader value of the useragent IP.</p>

    <p>The '<code>#</code>' hash character designates a comment line, otherwise

    each whitespace or newline separated entry is processed identically to

<usage>

    <p>The <directive>RemoteIPProxiesHeader</directive> directive specifies

    a header into which <module>mod_remoteip</module> will collect a list of

    all of the intermediate client IP addresses trusted to resolve the client

    all of the intermediate client IP addresses trusted to resolve the useragent

    IP of the request. Note that intermediate

    <directive>RemoteIPTrustedProxy</directive> addresses are recorded in

    this header, while any intermediate

<usage>

    <p>The <directive>RemoteIPTrustedProxy</directive> directive adds one

    or more addresses (or address blocks) to trust as presenting a valid

    RemoteIPHeader value of the client IP.  Unlike the

    RemoteIPHeader value of the useragent IP.  Unlike the

    <directive>RemoteIPInternalProxy</directive> 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

    2000::/3 block) are not trusted as the useragent IP, and are left in the

    <directive>RemoteIPHeader</directive> header's value.</p>

    <example><title>Trusted (Load Balancer) Example</title>

<usage>

    <p>The <directive>RemoteIPTrustedProxyList</directive> 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.</p>

    to trust as presenting a valid RemoteIPHeader value of the useragent IP.</p>

    <p>The '<code>#</code>' hash character designates a comment line, otherwise

    each whitespace or newline seperated entry is processed identically to

    /** local address */

    apr_sockaddr_t *local_addr;

    /** remote address */

    apr_sockaddr_t *peer_addr;

    apr_sockaddr_t *client_addr;

    /** Client's IP address */

    char *peer_ip;

    char *client_ip;

    /** Client's DNS name, if known.  NULL if DNS hasn't been checked,

     *  "" if it has and no address was found.  N.B. Only access this though

     * get_remote_host() */

    buf[len] = '\0';

    tbl = apr_table_make(r->pool, 10);

    qs_to_table(buf, tbl, r->pool);

    apr_sockaddr_ip_get(&ip, r->connection->peer_addr);

    apr_sockaddr_ip_get(&ip, r->connection->client_addr);

    hmserver.ip = ip;

    hmserver.port = 80;

    if (apr_table_get(tbl, "port") != NULL)

            if (!APR_STATUS_IS_EOF(rv) && ! APR_STATUS_IS_TIMEUP(rv))

                ap_log_error(APLOG_MARK, APLOG_INFO, rv, c->base_server, APLOGNO(01611)

                             "ProtocolEcho: Failure reading from %s",

                             c->peer_ip);

                             c->client_ip);

            break;

        }

            apr_brigade_cleanup(bb);

            ap_log_error(APLOG_MARK, APLOG_INFO, rv, c->base_server, APLOGNO(01612)

                         "ProtocolEcho: Error - read empty brigade from %s!",

                         c->peer_ip);

                         c->client_ip);

            break;

        }

        if (rv != APR_SUCCESS) {

            ap_log_error(APLOG_MARK, APLOG_INFO, rv, c->base_server, APLOGNO(01613)

                         "ProtocolEcho: Failure writing to %s",

                         c->peer_ip);

                         c->client_ip);

            break;

        }

        apr_brigade_cleanup(bb);