Query about Apache (httpd) dumpio log entry for the Request body which is coming NULL on Tomcat side

Question

Hi,

I am working on a hosted application running on Apache Tomcat 6.0.18 and it is hidden behind Apache (httpd). They are connected through mod_jk. We have take VPS and therefore Apache has been hosted as VirtualHost. The OS is CentOS 32 bit.

The problem is that very randomly Tomcat is getting NULL request (it may have some URL specific info but not the data). In order to debug this problem I enabled dumpio on apache to get the request body printed in logs. However I just got the following log entry,

[Tue Aug 18 04:18:16 2009] [debug] mod_dumpio.c(55): mod_dumpio: dumpio_in (metadata-EOS): 0 bytes

Also the thing to be noted that if I see access log, I could not find any entry with the same time stamp. Same can be seen in following two consecutive entries,

86.96.227.88 - app [18/Aug/2009:04:17:47 -0400] "POST /app/masters/ajaxReq.iajax HTTP/1.1" 400 - "http://server/app/masters/customer.do?action=menuLoad#" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30618)" 1036 180

86.96.227.88 - - [18/Aug/2009:04:18:49 -0400] "GET /app/ HTTP/1.1" 401 495 "-" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30618)" 716 848 8

Is it possible that Apache (HTTPD) is firing some autonomous requests to Tomcat?

I need help understanding this problem.

Answer 1

Tomcat has something called a RequestDumperValve, which dumps very verbose information about each request to the server log. It can be useful for seeing a lot of detail.

You'll find the config for this in tomcat's server.xml file:

        <!--
        <Valve className="org.apache.catalina.valves.RequestDumperValve" />
        -->

Uncomment it, restart Tomcat, and off you go. It won't solve your problem, obviously, but it may give you the information to track down those spurious requests.