IBM HTTP Server contains AfpaCache directive which turns the Fast Response Cache Accelerator function on or off. WebSphere is a series of applications which are built upon IBM HTTP Server.
Both IBM HTTP Server and Websphere are subject to a denial of service. This is caused by exhausting computer resources with malformed HTTP GET requests. A restart of the service is required inorder to gain normal functionality.
GET / HTTP/1.0\r\nuser-agent: 20000xnull\r\n\r\n
This request must be made multiple times before the system will freeze.