Running OS X Yosemite 10.10. So I have this weird issue with my Mac computer. In short, what happens is, I might have an internet connection for some time but then it would just drop out, if I un-plug and then re-plug the ethernet cable in to my mac, the internet will comeback for about 1 minute and then it will go down again, if you re-plug it again it will have internet again for another minute before it disconnects again. My suspicion is, it's requesting new settings every time I re-plug it but I do not understand why these settings won't work a minute after that. I have an internet connection with a dynamic IP provided by my ISP. My current set up is that the wan cable goes in to a router in my other room and then the router splits the internet connection with other ethernet connections to other computers in my place (total of 4). The internet on all computers works perfectly, however my Mac is having connection problems. I've tested the ethernet cable and the connection works perfectly with other computers. I have tried setting a static IP for my Mac computer in the network preference and I've reserved that static Ip in my router for my Mac using it's MAC address just in case there was a clash of ip's. This did not help, I've tried it 3 times with different Ip's, different dns (standard one 192.168.0.1 and 188.8.131.52) and it did not solve the issue. This is the typical setup I have in Network preference http://imgur.com/a/GeqjX at the moment it's 192.168.0.100 because I've reserved it in the router for it but when it's automatic it just gets 0.3 or 0.4 and it doesn't help. This is what happens when the connection fails and I try to access my router/the internet http://imgur.com/a/d6D5a , the last image is just a picture after I re plug the ethernet cable and I have internet for a brief second. This is what happens when the internet goes down and I try to access a website https://I.imgur.com/RolYoG7.png. When I run the Assist Me>Diagnostics on the Ethernet connection when it fails it tells me that the Ethernet connection is fine, Network Settings are fine but ISP,Internet and Server are not. (http://I.imgur.com/87UAJKq.png , this is the diagnostics, when it disconnects the ISP,Internet,Server are red), the diagnostics tell me to restart my router and continue after which, again I have internet for a few seconds and then it disconnects again. I've disconnected the computers I'm not using from my router and I have only 2 computers connected at the moment, my brothers and my Mac but this still happens even without the extra connections ( I was trying to trouble shoot the problem). What I've noticed is, when my brother is playing Battlefield 3, this issue is more prominent for me, when his computer is turned off all together it rarely ever happens, so that might be a clue, however I can't be conclusive if this is the source of the problem or if it's random luck. His computer obtains the ip automatically and I've already reserved the first allowed ip 192.168.0.100 , so I doubt it's an IP clash. Is it possible that his pc(internet activity,gaming) is throttling the connection for my computer somehow ? The thing with that is that every other computer is working fine on the network even if he is gaming or his computer is on, so it's only my computer. I even tested the cable and it worked fine with my laptop. I tried wifi on my mac and it has the same problems. Has anyone experienced something like this ? Does anyone know at which settings I should look in to my Network System Preference or in my router's settings ? Thanks in advance.