public class RemoteIpFilter extends java.lang.Object implements Filter
Servlet filter to integrate "X-Forwarded-For" and "X-Forwarded-Proto" HTTP headers.
Most of the design of this Servlet Filter is a port of mod_remoteip, this servlet filter replaces the apparent client remote IP address and hostname for the request with the IP address list presented by a proxy or a load balancer via a request headers (e.g. "X-Forwarded-For").
Another feature of this servlet filter is to replace the apparent scheme (http/https) and server port with the scheme presented by a proxy or a load balancer via a request header (e.g. "X-Forwarded-Proto").
This servlet filter proceeds as follows:
If the incoming request.getRemoteAddr()
matches the servlet
filter's list of internal or trusted proxies:
$remoteIpHeader
(default value x-forwarded-for
). Values are processed in right-to-left order.$protocolHeader
(e.g. x-forwarded-for
) equals to the value of
protocolHeaderHttpsValue
configuration parameter (default https
) then request.isSecure = true
,
request.scheme = https
and request.serverPort = 443
. Note that 443 can be overwritten with the
$httpsServerPort
configuration parameter.XForwardedFilter property | Description | Equivalent mod_remoteip directive | Format | Default Value |
---|---|---|---|---|
remoteIpHeader | Name of the Http Header read by this servlet filter that holds the list of traversed IP addresses starting from the requesting client | RemoteIPHeader | Compliant http header name | x-forwarded-for |
internalProxies | Regular expression that matches the IP addresses of internal proxies.
If they appear in the remoteIpHeader value, they will be
trusted and will not appear
in the proxiesHeader value |
RemoteIPInternalProxy | Regular expression (in the syntax supported by
java.util.regex ) |
10\.\d{1,3}\.\d{1,3}\.\d{1,3}|192\.168\.\d{1,3}\.\d{1,3}|
169\.254\.\d{1,3}\.\d{1,3}|127\.\d{1,3}\.\d{1,3}\.\d{1,3}|
172\.1[6-9]{1}\.\d{1,3}\.\d{1,3}|172\.2[0-9]{1}\.\d{1,3}\.\d{1,3}|
172\.3[0-1]{1}\.\d{1,3}\.\d{1,3}|
0:0:0:0:0:0:0:1|::1
By default, 10/8, 192.168/16, 169.254/16, 127/8, 172.16/12, and 0:0:0:0:0:0:0:1 are allowed. |
proxiesHeader | Name of the http header created by this servlet filter to hold the list of proxies that have been processed in the incoming
remoteIpHeader |
RemoteIPProxiesHeader | Compliant http header name | x-forwarded-by |
trustedProxies | Regular expression that matches the IP addresses of trusted proxies.
If they appear in the remoteIpHeader value, they will be
trusted and will appear in the proxiesHeader value |
RemoteIPTrustedProxy | Regular expression (in the syntax supported by
java.util.regex ) |
|
protocolHeader | Name of the http header read by this servlet filter that holds the flag that this request | N/A | Compliant http header name like X-Forwarded-Proto , X-Forwarded-Ssl or Front-End-Https |
null |
protocolHeaderHttpsValue | Value of the protocolHeader to indicate that it is an Https request |
N/A | String like https or ON |
https |
httpServerPort | Value returned by ServletRequest.getServerPort() when the protocolHeader indicates http protocol |
N/A | integer | 80 |
httpsServerPort | Value returned by ServletRequest.getServerPort() when the protocolHeader indicates https protocol |
N/A | integer | 443 |
Regular expression vs. IP address blocks: mod_remoteip
allows to use address blocks (e.g.
192.168/16
) to configure RemoteIPInternalProxy
and RemoteIPTrustedProxy
; as the JVM doesn't have a
library similar to apr_ipsubnet_test, we rely on
regular expressions.
Sample with internal proxies
XForwardedFilter configuration:
<filter>
<filter-name>RemoteIpFilter</filter-name>
<filter-class>org.apache.catalina.filters.RemoteIpFilter</filter-class>
<init-param>
<param-name>internalProxies</param-name>
<param-value>192\.168\.0\.10|192\.168\.0\.11</param-value>
</init-param>
<init-param>
<param-name>remoteIpHeader</param-name>
<param-value>x-forwarded-for</param-value>
</init-param>
<init-param>
<param-name>remoteIpProxiesHeader</param-name>
<param-value>x-forwarded-by</param-value>
</init-param>
<init-param>
<param-name>protocolHeader</param-name>
<param-value>x-forwarded-proto</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>RemoteIpFilter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
</filter-mapping>
property | Value Before RemoteIpFilter | Value After RemoteIpFilter |
---|---|---|
request.remoteAddr | 192.168.0.10 | 140.211.11.130 |
request.header['x-forwarded-for'] | 140.211.11.130, 192.168.0.10 | null |
request.header['x-forwarded-by'] | null | null |
request.header['x-forwarded-proto'] | https | https |
request.scheme | http | https |
request.secure | false | true |
request.serverPort | 80 | 443 |
x-forwarded-by
header is null because only internal proxies as been traversed by the request.
x-forwarded-by
is null because all the proxies are trusted or internal.
Sample with trusted proxies
RemoteIpFilter configuration:
<filter>
<filter-name>RemoteIpFilter</filter-name>
<filter-class>org.apache.catalina.filters.RemoteIpFilter</filter-class>
<init-param>
<param-name>internalProxies</param-name>
<param-value>192\.168\.0\.10|192\.168\.0\.11</param-value>
</init-param>
<init-param>
<param-name>remoteIpHeader</param-name>
<param-value>x-forwarded-for</param-value>
</init-param>
<init-param>
<param-name>remoteIpProxiesHeader</param-name>
<param-value>x-forwarded-by</param-value>
</init-param>
<init-param>
<param-name>trustedProxies</param-name>
<param-value>proxy1|proxy2</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>RemoteIpFilter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
</filter-mapping>
property | Value Before RemoteIpFilter | Value After RemoteIpFilter |
---|---|---|
request.remoteAddr | 192.168.0.10 | 140.211.11.130 |
request.header['x-forwarded-for'] | 140.211.11.130, proxy1, proxy2 | null |
request.header['x-forwarded-by'] | null | proxy1, proxy2 |
Note : proxy1
and proxy2
are both trusted proxies that come in x-forwarded-for
header, they both
are migrated in x-forwarded-by
header. x-forwarded-by
is null because all the proxies are trusted or internal.
Sample with internal and trusted proxies
RemoteIpFilter configuration:
<filter>
<filter-name>RemoteIpFilter</filter-name>
<filter-class>org.apache.catalina.filters.RemoteIpFilter</filter-class>
<init-param>
<param-name>internalProxies</param-name>
<param-value>192\.168\.0\.10|192\.168\.0\.11</param-value>
</init-param>
<init-param>
<param-name>remoteIpHeader</param-name>
<param-value>x-forwarded-for</param-value>
</init-param>
<init-param>
<param-name>remoteIpProxiesHeader</param-name>
<param-value>x-forwarded-by</param-value>
</init-param>
<init-param>
<param-name>trustedProxies</param-name>
<param-value>proxy1|proxy2</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>RemoteIpFilter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
</filter-mapping>
property | Value Before RemoteIpFilter | Value After RemoteIpFilter |
---|---|---|
request.remoteAddr | 192.168.0.10 | 140.211.11.130 |
request.header['x-forwarded-for'] | 140.211.11.130, proxy1, proxy2, 192.168.0.10 | null |
request.header['x-forwarded-by'] | null | proxy1, proxy2 |
Note : proxy1
and proxy2
are both trusted proxies that come in x-forwarded-for
header, they both
are migrated in x-forwarded-by
header. As 192.168.0.10
is an internal proxy, it does not appear in
x-forwarded-by
. x-forwarded-by
is null because all the proxies are trusted or internal.
Sample with an untrusted proxy
RemoteIpFilter configuration:
<filter>
<filter-name>RemoteIpFilter</filter-name>
<filter-class>org.apache.catalina.filters.RemoteIpFilter</filter-class>
<init-param>
<param-name>internalProxies</param-name>
<param-value>192\.168\.0\.10|192\.168\.0\.11</param-value>
</init-param>
<init-param>
<param-name>remoteIpHeader</param-name>
<param-value>x-forwarded-for</param-value>
</init-param>
<init-param>
<param-name>remoteIpProxiesHeader</param-name>
<param-value>x-forwarded-by</param-value>
</init-param>
<init-param>
<param-name>trustedProxies</param-name>
<param-value>proxy1|proxy2</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>RemoteIpFilter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
</filter-mapping>
property | Value Before RemoteIpFilter | Value After RemoteIpFilter |
---|---|---|
request.remoteAddr | 192.168.0.10 | untrusted-proxy |
request.header['x-forwarded-for'] | 140.211.11.130, untrusted-proxy, proxy1 | 140.211.11.130 |
request.header['x-forwarded-by'] | null | proxy1 |
Note : x-forwarded-by
holds the trusted proxy proxy1
. x-forwarded-by
holds
140.211.11.130
because untrusted-proxy
is not trusted and thus, we can not trust that
untrusted-proxy
is the actual remote ip. request.remoteAddr
is untrusted-proxy
that is an IP
verified by proxy1
.
Modifier and Type | Class and Description |
---|---|
static class |
RemoteIpFilter.XForwardedRequest |
Modifier and Type | Field and Description |
---|---|
protected static java.lang.String |
CHANGE_LOCAL_PORT_PARAMETER |
protected static java.lang.String |
HTTP_SERVER_PORT_PARAMETER |
protected static java.lang.String |
HTTPS_SERVER_PORT_PARAMETER |
protected static java.lang.String |
INTERNAL_PROXIES_PARAMETER |
protected static java.lang.String |
PORT_HEADER_PARAMETER |
protected static java.lang.String |
PROTOCOL_HEADER_HTTPS_VALUE_PARAMETER |
protected static java.lang.String |
PROTOCOL_HEADER_PARAMETER |
protected static java.lang.String |
PROXIES_HEADER_PARAMETER |
protected static java.lang.String |
REMOTE_IP_HEADER_PARAMETER |
protected static java.lang.String |
TRUSTED_PROXIES_PARAMETER |
Constructor and Description |
---|
RemoteIpFilter() |
Modifier and Type | Method and Description |
---|---|
protected static java.lang.String[] |
commaDelimitedListToStringArray(java.lang.String commaDelimitedStrings)
Convert a given comma delimited list of regular expressions into an array of String
|
void |
destroy()
Called by the web container to indicate to a filter that it is being
taken out of service.
|
void |
doFilter(HttpServletRequest request,
HttpServletResponse response,
FilterChain chain) |
void |
doFilter(ServletRequest request,
ServletResponse response,
FilterChain chain)
Wrap the incoming
request in a RemoteIpFilter.XForwardedRequest if the http header x-forwarded-for is not empty. |
int |
getHttpsServerPort() |
java.util.regex.Pattern |
getInternalProxies() |
java.lang.String |
getPortHeader() |
java.lang.String |
getProtocolHeader() |
java.lang.String |
getProtocolHeaderHttpsValue() |
java.lang.String |
getProxiesHeader() |
java.lang.String |
getRemoteIpHeader() |
boolean |
getRequestAttributesEnabled() |
java.util.regex.Pattern |
getTrustedProxies() |
void |
init(FilterConfig filterConfig)
Called by the web container to indicate to a filter that it is being
placed into service.
|
boolean |
isChangeLocalPort() |
protected static java.lang.String |
listToCommaDelimitedString(java.util.List<java.lang.String> stringList)
Convert an array of strings in a comma delimited string
|
void |
setChangeLocalPort(boolean changeLocalPort)
If
true , the return values for both ServletRequest.getLocalPort() and ServletRequest.getServerPort()
wil be modified by this Filter rather than just
ServletRequest.getServerPort() . |
void |
setHttpServerPort(int httpServerPort)
Server Port value if the
protocolHeader indicates HTTP (i.e. |
void |
setHttpsServerPort(int httpsServerPort)
Server Port value if the
protocolHeader indicates HTTPS
Default value : 443
|
void |
setInternalProxies(java.lang.String internalProxies)
Regular expression that defines the internal proxies.
|
void |
setPortHeader(java.lang.String portHeader)
Header that holds the incoming port, usally named
X-Forwarded-Port . |
void |
setProtocolHeader(java.lang.String protocolHeader)
Header that holds the incoming protocol, usally named
X-Forwarded-Proto . |
void |
setProtocolHeaderHttpsValue(java.lang.String protocolHeaderHttpsValue)
Case insensitive value of the protocol header to indicate that the incoming http request uses HTTPS.
|
void |
setProxiesHeader(java.lang.String proxiesHeader)
The proxiesHeader directive specifies a header into which mod_remoteip will collect a list of all of the intermediate client IP
addresses trusted to resolve the actual remote IP.
|
void |
setRemoteIpHeader(java.lang.String remoteIpHeader)
Name of the http header from which the remote ip is extracted.
|
void |
setRequestAttributesEnabled(boolean requestAttributesEnabled)
Should this filter set request attributes for IP address, Hostname,
protocol and port used for the request?
|
void |
setTrustedProxies(java.lang.String trustedProxies)
Regular expression defining proxies that are trusted when they appear in
the
remoteIpHeader header. |
protected static final java.lang.String HTTP_SERVER_PORT_PARAMETER
protected static final java.lang.String HTTPS_SERVER_PORT_PARAMETER
protected static final java.lang.String INTERNAL_PROXIES_PARAMETER
protected static final java.lang.String PROTOCOL_HEADER_PARAMETER
protected static final java.lang.String PROTOCOL_HEADER_HTTPS_VALUE_PARAMETER
protected static final java.lang.String PORT_HEADER_PARAMETER
protected static final java.lang.String CHANGE_LOCAL_PORT_PARAMETER
protected static final java.lang.String PROXIES_HEADER_PARAMETER
protected static final java.lang.String REMOTE_IP_HEADER_PARAMETER
protected static final java.lang.String TRUSTED_PROXIES_PARAMETER
protected static java.lang.String[] commaDelimitedListToStringArray(java.lang.String commaDelimitedStrings)
null
)protected static java.lang.String listToCommaDelimitedString(java.util.List<java.lang.String> stringList)
public void destroy()
javax.servlet.Filter
public void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws java.io.IOException, ServletException
java.io.IOException
ServletException
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws java.io.IOException, ServletException
request
in a RemoteIpFilter.XForwardedRequest
if the http header x-forwarded-for
is not empty.doFilter
in interface Filter
request
- The request to processresponse
- The response associated with the requestchain
- Provides access to the next filter in the chain for this
filter to pass the request and response to for further
processingjava.io.IOException
- if an I/O error occurs during this filter's
processing of the requestServletException
- if the processing fails for any other reasonpublic boolean isChangeLocalPort()
public int getHttpsServerPort()
public java.util.regex.Pattern getInternalProxies()
public java.lang.String getProtocolHeader()
public java.lang.String getPortHeader()
public java.lang.String getProtocolHeaderHttpsValue()
public java.lang.String getProxiesHeader()
public java.lang.String getRemoteIpHeader()
public boolean getRequestAttributesEnabled()
true
if the attributes will be logged, otherwise
false
setRequestAttributesEnabled(boolean)
public java.util.regex.Pattern getTrustedProxies()
public void init(FilterConfig filterConfig) throws ServletException
javax.servlet.Filter
The web container cannot place the filter into service if the init method either:
init
in interface Filter
filterConfig
- The configuration information associated with the
filter instance being initialisedServletException
- if the initialisation failspublic void setChangeLocalPort(boolean changeLocalPort)
If true
, the return values for both ServletRequest.getLocalPort()
and ServletRequest.getServerPort()
wil be modified by this Filter rather than just
ServletRequest.getServerPort()
.
Default value : false
public void setHttpServerPort(int httpServerPort)
Server Port value if the protocolHeader
indicates HTTP (i.e. protocolHeader
is not null and
has a value different of protocolHeaderHttpsValue
).
Default value : 80
public void setHttpsServerPort(int httpsServerPort)
Server Port value if the protocolHeader
indicates HTTPS
Default value : 443
public void setInternalProxies(java.lang.String internalProxies)
Regular expression that defines the internal proxies.
Default value : 10\.\d{1,3}\.\d{1,3}\.\d{1,3}|192\.168\.\d{1,3}\.\d{1,3}|169\.254.\d{1,3}.\d{1,3}|127\.\d{1,3}\.\d{1,3}\.\d{1,3}|0:0:0:0:0:0:0:1
public void setPortHeader(java.lang.String portHeader)
Header that holds the incoming port, usally named
X-Forwarded-Port
. If null
,
httpServerPort
or httpsServerPort
will be used.
Default value : null
public void setProtocolHeader(java.lang.String protocolHeader)
Header that holds the incoming protocol, usally named X-Forwarded-Proto
. If null
, request.scheme and
request.secure will not be modified.
Default value : null
public void setProtocolHeaderHttpsValue(java.lang.String protocolHeaderHttpsValue)
Case insensitive value of the protocol header to indicate that the incoming http request uses HTTPS.
Default value : https
public void setProxiesHeader(java.lang.String proxiesHeader)
The proxiesHeader directive specifies a header into which mod_remoteip will collect a list of all of the intermediate client IP addresses trusted to resolve the actual remote IP. Note that intermediate RemoteIPTrustedProxy addresses are recorded in this header, while any intermediate RemoteIPInternalProxy addresses are discarded.
Name of the http header that holds the list of trusted proxies that has been traversed by the http request.
The value of this header can be comma delimited.
Default value : X-Forwarded-By
public void setRemoteIpHeader(java.lang.String remoteIpHeader)
Name of the http header from which the remote ip is extracted.
The value of this header can be comma delimited.
Default value : X-Forwarded-For
public void setRequestAttributesEnabled(boolean requestAttributesEnabled)
AccessLog
which will otherwise log the
original values. Default is true
.
The attributes set are:
requestAttributesEnabled
- true
causes the attributes
to be set, false
disables
the setting of the attributes.public void setTrustedProxies(java.lang.String trustedProxies)
Regular expression defining proxies that are trusted when they appear in
the remoteIpHeader
header.
Default value : empty list, no external proxy is trusted.
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