HTTP Forwarded and X-Forwarded-* header support means that programmers and applications can obtain the original client endpoint information presented by a proxy or a load balancer using the Forwarded or X-Forwarded-* headers instead of the current TCP connected endpoint. This information can be retrieved using certain Servlet API calls or the NCSA Access Log.
You can use the Forwarded and X-Forwarded-* headers by configuring a new element in the server.xml. Optionally, you can provide a regular expression that declares the internal/trusted proxy servers. In addition, you can optionally configure a Boolean type attribute that, if the HTTP Channel has verified the specific remote client information, the NCSA Access Log reflects the Forwarded and X-Forwarded-* headers when recording the remote IP, host, and/or the request protocol.