ATG Rest Services - capture IP of caller

Question

Is it possible to capture the IP address of who is calling a REST service?
The reason I am asking is that we seem to be having a lot of the following errors in our log file:
ERROR [RepositoryServlet??] Error code: 500 CONTAINER:atg.repository.RepositorySecurityException; SOURCE:atg.security.PermissionDeniedException: You do not have read access to the category item descriptor.
null
atg.rest.RestException??: CONTAINER:atg.repository.RepositorySecurityException; SOURCE:atg.security.PermissionDeniedException: You do not have read access to the category item des criptor.
Now, We have a mobile site which makes use of the REST services and they are all set up with the correct login/security.
What I am trying to determine is who else is making these REST calls - something internal - or some unkown entity outside the application. I figured that if I can capture the IP then that will narrow down things. If it is outside, then the system is operating as expected and the error is justified. But if it is internal then need to do a bit more digging of what the root cause is.
thanks

Answer 1

I added the following to my method:
               if ("/rest".equalsIgnoreCase(pRequest.getContextPath()))
                    String clientAddressStr = pRequest.getHeader("x-forwarded-for");
                    if (StringUtils.isNotBlank(clientAddressStr))
                         //clientAddressStr will be of format: clientIp, Proxy1, Proxy2
                         String[] clientAddressArr = clientAddressStr.split(",");
                         if (isLoggingInfo())
                              logInfo("service(DynamoHttpServletRequest, DynamoHttpServletResponse) - IP Address is:: " + clientAddressArr[0].trim()); //$NON-NLS-1$
This does not work - the line
String clientAddressStr = pRequest.getHeader("x-forwarded-for");
always comes back as null.
Any issue of just grabbing the remote addr from the request?