In response to your question:
can you post screenshot in postimages.org and teach me how to identify such malicious peers?
Here is an image showing status codes of misbehaving clients. I was having a large number of clients with the same status code of "metadata request overflow" as you will see in the image. Almost all of these errors were generated by the same client software which was mostly likely a bot. I have my own web space, so I will post the image there.
(link removed by Mod - please re-post the image with IP's blurred)