large amount of R in server-status

[Dietmar Müller <oas.public@xxxxxxxxx>]

Hi,

I use since long time the apache in version 2.0 on windows 2000 (SP4).
Since 4 weeks I can see (some times per day) many R in server-status. Sometimes so much that the server run full and stop working because all threads are used. I search in web and generally the response is that it have to do with dos but I'm not sure (or can't believe that)

When I watch over some time the serverstatus I can see sometimes requests staying in R status until the configparameter timeout=300 (default) kick the request out. Sometimes this R staying requests use more then 50% from my threads and then after timeout all works like expexcted. Sometimes the complete webserver is blocked.

Current I have 450 threads on apache and in background 2 clustered tomcats with a 200 threads.

Can anybody explain me how it is possible that some (?) can send a rq to a webserver and don't finish the rq that the server wait for it? How can I solve such situations?

Further: how can I identify and/or analyze a problem like this. I have now a situation where I have log the network trafik with wireshark.

This problem start (about) at a time when we switch to a new provider.

I have now version 2.0.57 but I have the problem also in the latest version from the 2.0 tree.

If someone has some hint and or experience how to identify the problem --> thanks for any comment / hint

regards Dietmar