A Valve element represents a component that will be inserted into the request processing pipeline for the associated Catalina container (Engine, Host, or Context). Individual Valves have distinct processing capabilities, and are described individually below.

The description below uses the variable name $CATALINA_BASE to refer the base directory against which most relative paths are resolved. If you have not configured Tomcat 6 for multiple instances by setting a CATALINA_BASE directory, then $CATALINA_BASE will be set to the value of $CATALINA_HOME, the directory into which you have installed Tomcat 6.

Introduction

The Access Log Valve creates log files in the same format as those created by standard web servers. These logs can later be analyzed by standard log analysis tools to track page hit counts, user session activity, and so on. The files produces by this Valve are rolled over nightly at midnight. This Valve may be associated with any Catalina container (Context, Host, or Engine), and will record ALL requests processed by that container.

Attributes

The Access Log Valve supports the following configuration attributes: Attribute Description className Java class name of the implementation to use. This MUST be set to org.apache.catalina.valves.AccessLogValve to use the default access log valve. directory Absolute or relative pathname of a directory in which log files created by this valve will be placed. If a relative path is specified, it is interpreted as relative to $CATALINA_BASE. If no directory attribute is specified, the default value is "logs" (relative to $CATALINA_BASE). pattern A formatting layout identifying the various information fields from the request and response to be logged, or the word common or combined to select a standard format. See below for more information on configuring this attribute. Note that the optimized access does only support common and combined as the value for this attribute. prefix The prefix added to the start of each log file's name. If not specified, the default value is "access_log.". To specify no prefix, use a zero-length string. resolveHosts Set to true to convert the IP address of the remote host into the corresponding host name via a DNS lookup. Set to false to skip this lookup, and report the remote IP address instead. suffix The suffix added to the end of each log file's name. If not specified, the default value is "". To specify no suffix, use a zero-length string. rotatable Flag to determine if log rotation should occur. If set to false, then this file is never rotated and fileDateFormat is ignored. Use with caution! Default value: true condition Turns on conditional logging. If set, requests will be logged only if ServletRequest.getAttribute() is null. For example, if this value is set to junk, then a particular request will only be logged if ServletRequest.getAttribute("junk") == null. The use of Filters is an easy way to set/unset the attribute in the ServletRequest on many different requests. fileDateFormat Allows a customized date format in the access log file name. The date format also decides how often the file is rotated. If you wish to rotate every hour, then set this value to: yyyy-MM-dd.HH buffered Flag to determine if logging will be buffered. If set to false, then access logging will be written after each request. Default value: true Values for the pattern attribute are made up of literal text strings, combined with pattern identifiers prefixed by the "%" character to cause replacement by the corresponding variable value from the current request and response. The following pattern codes are supported: %a - Remote IP address %A - Local IP address %b - Bytes sent, excluding HTTP headers, or '-' if zero %B - Bytes sent, excluding HTTP headers %h - Remote host name (or IP address if resolveHosts is false) %H - Request protocol %l - Remote logical username from identd (always returns '-') %m - Request method (GET, POST, etc.) %p - Local port on which this request was received %q - Query string (prepended with a '?' if it exists) %r - First line of the request (method and request URI) %s - HTTP status code of the response %S - User session ID %t - Date and time, in Common Log Format %u - Remote user that was authenticated (if any), else '-' %U - Requested URL path %v - Local server name %D - Time taken to process the request, in millis %T - Time taken to process the request, in seconds %I - current request thread name (can compare later with stacktraces) There is also support to write information from the cookie, incoming header, the Session or something else in the ServletRequest. It is modeled after the apache syntax: %{xxx}i for incoming headers %{xxx}o for outgoing response headers %{xxx}c for a specific cookie %{xxx}r xxx is an attribute in the ServletRequest %{xxx}s xxx is an attribute in the HttpSession The shorthand pattern name common (which is also the default) corresponds to '%h %l %u %t "%r" %s %b'. The shorthand pattern name combined appends the values of the Referer and User-Agent headers, each in double quotes, to the common pattern described in the previous paragraph.

Introduction

The Remote Address Filter allows you to compare the IP address of the client that submitted this request against one or more regular expressions, and either allow the request to continue or refuse to process the request from this client. A Remote Address Filter can be associated with any Catalina container (Engine, Host, or Context), and must accept any request presented to this container for processing before it will be passed on. The syntax for regular expressions is different than that for 'standard' wildcard matching. Tomcat uses the java.util.regex package. Please consult the Java documentation for details of the expressions supported.

Attributes

The Remote Address Filter supports the following configuration attributes: Attribute Description className Java class name of the implementation to use. This MUST be set to org.apache.catalina.valves.RemoteAddrValve. allow A comma-separated list of regular expression patterns that the remote client's IP address is compared to. If this attribute is specified, the remote address MUST match for this request to be accepted. If this attribute is not specified, all requests will be accepted UNLESS the remote address matches a deny pattern. deny A comma-separated list of regular expression patterns that the remote client's IP address is compared to. If this attribute is specified, the remote address MUST NOT match for this request to be accepted. If this attribute is not specified, request acceptance is governed solely by the accept attribute.

Introduction

The Remote Host Filter allows you to compare the hostname of the client that submitted this request against one or more regular expressions, and either allow the request to continue or refuse to process the request from this client. A Remote Host Filter can be associated with any Catalina container (Engine, Host, or Context), and must accept any request presented to this container for processing before it will be passed on. The syntax for regular expressions is different than that for 'standard' wildcard matching. Tomcat uses the java.util.regex package. Please consult the Java documentation for details of the expressions supported.

Attributes

The Remote Host Filter supports the following configuration attributes: Attribute Description className Java class name of the implementation to use. This MUST be set to org.apache.catalina.valves.RemoteHostValve. allow A comma-separated list of regular expression patterns that the remote client's hostname is compared to. If this attribute is specified, the remote hostname MUST match for this request to be accepted. If this attribute is not specified, all requests will be accepted UNLESS the remote hostname matches a deny pattern. deny A comma-separated list of regular expression patterns that the remote client's hostname is compared to. If this attribute is specified, the remote hostname MUST NOT match for this request to be accepted. If this attribute is not specified, request acceptance is governed solely by the accept attribute.

Introduction

The Request Dumper Valve is a useful tool in debugging interactions with a client application (or browser) that is sending HTTP requests to your Tomcat-based server. When configured, it causes details about each request processed by its associated Engine, Host, or Context to be logged according to the logging configuration for that container. WARNING: Using this valve has side-effects. The output from this valve includes any parameters included with the request. The parameters will be decoded using the default platform encoding. Any subsequent calls to request.setCharacterEncoding() within the web application will have no effect.

Attributes

The Request Dumper Valve supports the following configuration attributes: Attribute Description className Java class name of the implementation to use. This MUST be set to org.apache.catalina.valves.RequestDumperValve.

Introduction

The Single Sign On Vale is utilized when you wish to give users the ability to sign on to any one of the web applications associated with your virtual host, and then have their identity recognized by all other web applications on the same virtual host. See the Single Sign On special feature on the Host element for more information.

Attributes

The Single Sign On Valve supports the following configuration attributes: Attribute Description className Java class name of the implementation to use. This MUST be set to org.apache.catalina.authenticator.SingleSignOn. requireReauthentication Default false. Flag to determine whether each request needs to be reauthenticated to the security Realm. If "true", this Valve uses cached security credentials (username and password) to reauthenticate to the Realm each request associated with an SSO session. If "false", the Valve can itself authenticate requests based on the presence of a valid SSO cookie, without rechecking with the Realm. cookieDomain Sets the host domain to be used for sso cookies.

Introduction

The Basic Authenticator Valve is automatically added to any Context that is configured to use BASIC authentication. If any non-default settings are required, the valve may be configured within Context element with the required values.

Attributes

The Basic Authenticator Valve supports the following configuration attributes: Attribute Description className Java class name of the implementation to use. This MUST be set to org.apache.catalina.authenticator.BasicAuthenticator. changeSessionIdOnAuthentication Controls if the session ID is changed if a session exists at the point where users are authenticated. This is to prevent session fixation attacks. If not set, the default value of true will be used. disableProxyCaching Controls the caching of pages that are protected by security constraints. Setting this to false may help work around caching issues in some browsers but will also cause secured pages to be cached by proxies which will almost certainly be a security issue. securePagesWithPragma offers an alternative, secure, workaround for browser caching issues. If not set, the default value of true will be used. securePagesWithPragma Controls the caching of pages that are protected by security constraints. Setting this to false may help work around caching issues in some browsers by using Cache-Control: private rather than the default of Pragma: No-cache and Cache-control: No-cache. If not set, the default value of true will be used.

Introduction

The Digest Authenticator Valve is automatically added to any Context that is configured to use DIGEST authentication. If any non-default settings are required, the valve may be configured within Context element with the required values.

Attributes

The Digest Authenticator Valve supports the following configuration attributes: Attribute Description cache Should we cache authenticated Principals if the request is part of an HTTP session? If not specified, the default value of false will be used. className Java class name of the implementation to use. This MUST be set to org.apache.catalina.authenticator.DigestAuthenticator. changeSessionIdOnAuthentication Controls if the session ID is changed if a session exists at the point where users are authenticated. This is to prevent session fixation attacks. If not set, the default value of true will be used. cnonceCacheSize To protect against replay attacks, the DIGEST authenticator tracks client nonce and nonce count values. This attribute controls the size of that cache. If not specified, the default value of 1000 is used. disableProxyCaching Controls the caching of pages that are protected by security constraints. Setting this to false may help work around caching issues in some browsers but will also cause secured pages to be cached by proxies which will almost certainly be a security issue. securePagesWithPragma offers an alternative, secure, workaround for browser caching issues. If not set, the default value of true will be used. key The secret key used by digest authentication. If not set, a secure random value is generated. This should normally only be set when it is necessary to keep key values constant either across server restarts and/or across a cluster. nonceCacheSize To protect against replay attacks, the DIGEST authenticator tracks server nonce and nonce count values. This attribute controls the size of that cache. If not specified, the default value of 1000 is used. nonceValidity The time, in milliseconds, that a server generated nonce will be considered valid for use in authentication. If not specified, the default value of 300000 (5 minutes) will be used. opaque The opaque server string used by digest authentication. If not set, a random value is generated. This should normally only be set when it is necessary to keep opaque values constant either across server restarts and/or across a cluster. securePagesWithPragma Controls the caching of pages that are protected by security constraints. Setting this to false may help work around caching issues in some browsers by using Cache-Control: private rather than the default of Pragma: No-cache and Cache-control: No-cache. If not set, the default value of true will be used. validateUri Should the URI be validated as required by RFC2617? If not specified, the default value of true will be used. This should normally only be set when Tomcat is located behind a reverse proxy and the proxy is modifying the URI passed to Tomcat such that DIGEST authentication always fails.

Introduction

The Form Authenticator Valve is automatically added to any Context that is configured to use FORM authentication. If any non-default settings are required, the valve may be configured within Context element with the required values.

Attributes

The Form Authenticator Valve supports the following configuration attributes: Attribute Description className Java class name of the implementation to use. This MUST be set to org.apache.catalina.authenticator.FormAuthenticator. changeSessionIdOnAuthentication Controls if the session ID is changed if a session exists at the point where users are authenticated. This is to prevent session fixation attacks. If not set, the default value of true will be used. characterEncoding Character encoding to use to read the username and password parameters from the request. If not set, the encoding of the request body will be used. disableProxyCaching Controls the caching of pages that are protected by security constraints. Setting this to false may help work around caching issues in some browsers but will also cause secured pages to be cached by proxies which will almost certainly be a security issue. securePagesWithPragma offers an alternative, secure, workaround for browser caching issues. If not set, the default value of true will be used. key The secret key used by digest authenticaion. If not set, a secure random value is generated. This should normally only be set when it is necessary to keep key values constant either across server restarts and/or across a cluster. nonceValidity The time, in milliseconds, that a server generated nonce will be considered valid for use in authentication. If not specified, the default value of 300000 (5 minutes) will be used. opaque The opaque server string used by digest authentication. If not set, a random value is generated. This should normally only be set when it is necessary to keep opaque values constant either across server restarts and/or across a cluster. securePagesWithPragma Controls the caching of pages that are protected by security constraints. Setting this to false may help work around caching issues in some browsers by using Cache-Control: private rather than the default of Pragma: No-cache and Cache-control: No-cache. If not set, the default value of true will be used.

Introduction

The SSL Authenticator Valve is automatically added to any Context that is configured to use SSL authentication. If any non-default settings are required, the valve may be configured within Context element with the required values.

Attributes

The SSL Authenticator Valve supports the following configuration attributes: Attribute Description className Java class name of the implementation to use. This MUST be set to org.apache.catalina.authenticator.SSLAuthenticator. changeSessionIdOnAuthentication Controls if the session ID is changed if a session exists at the point where users are authenticated. This is to prevent session fixation attacks. If not set, the default value of true will be used. disableProxyCaching Controls the caching of pages that are protected by security constraints. Setting this to false may help work around caching issues in some browsers but will also cause secured pages to be cached by proxies which will almost certainly be a security issue. securePagesWithPragma offers an alternative, secure, workaround for browser caching issues. If not set, the default value of true will be used. securePagesWithPragma Controls the caching of pages that are protected by security constraints. Setting this to false may help work around caching issues in some browsers by using Cache-Control: private rather than the default of Pragma: No-cache and Cache-control: No-cache. If not set, the default value of true will be used.

Introduction

Microsoft operating systems have two WebDAV clients. One is used with port 80, the other is used for all other ports. The implementation used with port 80 does not adhere to the WebDAV specification and fails when trying to communicate with the Tomcat WebDAV Servlet. This valve provides a fix for this by forcing the use of the WebDAV implementation that works, even when connecting via port 80. This Valve may be used at the Engine, Host or Context level as required. Normally, this Valve would be used at the Context level.

Attributes

The WebDAV Fix Valve supports the following configuration attributes: Attribute Description className Java class name of the implementation to use. This MUST be set to org.apache.catalina.valves.WebdavFixValve.

Introduction

Tomcat port of mod_remoteip, this valve 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 valve 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 Valve may be used at the Engine, Host or Context level as required. Normally, this Valve would be used at the Engine level. If used in conjunction with Remote Address/Host valves then this valve should be defined first to ensure that the correct client IP address is presented to the Remote Address/Host valves.

Attributes

The Remote IP Valve supports the following configuration attributes: Attribute Description className Java class name of the implementation to use. This MUST be set to org.apache.catalina.valves.RemoteIpValve. remoteIPHeader Name of the HTTP Header read by this valve that holds the list of traversed IP addresses starting from the requesting client. If not specified, the default of x-forwarded-for is used. internalProxies List of internal proxies' IP addresses as comma separated regular expressions. If they appear in the remoteIpHeader value, they will be trusted and will not appear in the proxiesHeader value. If not specified the default value of 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} will be used. proxiesHeader Name of the HTTP header created by this valve to hold the list of proxies that have been processed in the incoming remoteIpHeader. If not specified, the default of x-forwarded-by is used. trustedProxies List of trusted proxies' IP addresses as comma separated regular expressions. If they appear in the remoteIpHeader value, they will be trusted and will appear in the proxiesHeader value. If not specified, no proxies will be trusted. protocolHeader Name of the HTTP Header read by this valve that holds the protocol used by the client to connect to the proxy. If not specified, the default of null is used. protocolHeaderHttpsValue Value of the protocolHeader to indicate that it is an HTTPS request. If not specified, the default of https is used.