To mitigate a single-session DoS attack, you
would still
Configure
DoS Protection Against Flooding of New Sessions in advance.
At some point after you configure the feature, a session might be
established before you realize a DoS attack (from the IP address
of that session) is underway. When you see a single-session DoS
attack, perform the following task to end the session, so that subsequent connection
attempts from that IP address trigger the DoS protection against
flooding of new sessions.