In mathematics, the study of combinations refers to the number of ways one can select items from a group disregarding order; the study of permutations refers to the number of ways one can permute, or arrange, items into a sequence. Given that each entry in a binary string must be either a 1 or a 0, what is the total number of addresses that can be encoded using a 32-bit binary string? Is this a combination or permutation problem? Justify your answer.

In IPv6, 128 bit, binary strings are used for addressing. How many addresses can be encoded using 128 bits? Is this a combination or permutation problem? Justify your answer.

In IPv4, how many addresses contain exactly eight 1s?