I'm trying to learn about networking on my own and right now, mainly from watching youtube so it's easy to get confused. I have a regular home set-up with one modem and one wi-fi router which is the only gateway. I'm trying to understand the process by which my computer gets its IP address each time I turn it on and my questions:
1. I'm running Win 7 on my computer and in my network setting, I have DHCP enabled and an IP assigned. But who really assigns it? My computer or router? If it's the former, how does it avoid conflicting with other hosts on the same network? Also, when I checked my IP address online eg whatismyipaddress.com, it gives a different value. Does that mean I'm using two layers of DHCP services ie one on my router or computer and the other an external server which my guess is my ISP's?
2. for an external DHCP server eg provided by an ISP, can the same IP be leased to more than one host that are on different networks at the same time eg say you have 3 homes, A,B,C, where each have their own modem, modem A, modem B and modem C(all by the same ISP) and their own computer, computer A, computer B, computer C, then is it possible to have each computer, namely computer A, computer B and computer C gets assigned the same IP addr at the same time? I mean afterall, their modems have different IP addrs.