Login and Logouts IP's

About two weeks ago our site started getting a bunch of 404 page hits to non-existent pages. So Ive been digging around trying to figure out what is going on and came across WordFence. So I dove in and what I have found it rather confusing to me. All these hits are coming from similar IP’s. At first I thought great I will just block them but what is troubling me is that when i look at my login and logouts it shows me logging in with those same ips that arent my IP. Any ideas of what is going on?