Hey. I rent a basement apartment from a family and use ethernet over power to obtain internet to my 27" Mid 2012 iMac. I recently bought a TP-Link Tl-WA801ND Access Point to broadcast my own network in my apartment and set it up to ensure that DHCP was off and all that stuff. Started connecting all my devices (iPad Mini, Iphone 5s, mid 2013 MBP, PS3, etc.) with out any problems. They all work and can reach the internet fine. When I attempted to connect my iMac, the computer WILL NOT work. It self assigns its own IP address, which is 18.104.22.168 (Not sure where its getting that idea) and the AP is set up to get Ip address from the FIOS router up stairs which is 192.168.1.xx . Any ideas? I am at a complete loss and have no idea what else it could be. Update: What I've narrowed it down to: It is not the problem with the AP, because it is configured so that every device I've tried, except for the iMac works with the AP. It is not the problem with my internet connect, because all other devices works, except for iMac. It is not the problem with my internet card on the iMac, because I was able to connect with the FIOS Router the family has upstair but I do not want to use. It is not the hardware problem, like I said, ethernet socket, internet card, they all work. It has nothing to do with the software update, the software is up to date, running on Mac OS X, 10.10 Yosemite It has to be a software issue, something to do with the configuration of the network. I've already looked everywhere on the apple discussions, I found similar problems, but they were either unresolved, or unrelated to my problem. So what did I mess up on?