Consider a system that generates 10 million audit records per day.Assume that, on average, there are 10 attacks per day on this systemand each attack is reflected in 20 records. If the intrusion-detectionsystem has a true-alarm rate of 0.6 and a false-alarm rate of 0.0005,what percentage of alarms generated by the system correspond to realintrusions?
Lecture 7 Web caches (proxy server) o Goal is to satisfy client requests withoug involving the origin server o Basically recently requested objects are housed in the cache. The browser sends HTTP requests to the cache and if it is there it returns right away, otherwise it requests the obj from the origin server and returns that o Cache can also rend a request to the origin server to check if the requested obect has been modified since it was stored in the cache. If it has been, the cache requests the new version and stores that, then returns the new obj to the server Electronic mail o Three componenets User agents