Tomcat access logs will important information about resource requested,timestamp and IP of the requesting machine and they are many information we can capture in access logs. In case if we are running tomcat behind proxy or load balancer, We will not able to see where request is originating. So in such case we have to modify access log settings to capture those.

<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log." suffix=".txt"
               pattern="%{X-Forwarded-For}i %h %l %u %t &quot;%r&quot; %s %b" />

X-Forwarded-For gives the request originating IP in tomcat access log