Shuffling Theory

1. If there are n computers, among which 1 is vulnerable. Each computer is assigned an IP address, the attackers probe randomly on the IP address to check whether its corresponding computer is vulnerable. If the IP addresses of all computer randomly shuffled after each attacker's probe. What is the probability that the attacker will find the vulnerable machine?

Answer:

$Pr(0<x<n) = 1 - (1-1/n)^n = 1 - 1/e$




Reference
[1] Analysis of Network Address Shuffling as a Moving Target Defense, by Thomas E. Carroll, in ICC14