Implementing NetScaler VPX™ - Second Edition

HTTP DoS protection

In some cases, it might not be that easy to detect an attack. For instance, in a suspected HTTP DDoS attack, a web server may be attacked with legitimate traffic, and therefore they are regular HTTP requests. This is where we can use HTTP DoS protection. HTTP DoS protection allows NetScaler to respond with a JavaScript challenge to all incoming HTTP requests. Now, since an HTTP DDoS attack is typically done using a cluster of multiple nodes running a scripted attack, these nodes do not support any form of JavaScript request. Therefore, when they cannot respond to the JavaScript challenge, NetScaler closes the connection. Regular users who surf through a regular browser that supports JavaScript are therefore granted access. ...