Question Internet stops working completely if a certain computer is connected via ethernet


Dec 2, 2014
So i have a unique situation here which ive never seen. Due to covid the wife started working from home, and brought her work computer home( 2 months ago) Lately for some reason, our internet will stop working. Ive pinpointed it to the ethernet connection on her computer, and can reproduce 100% of the time.

When her work computer is plugged in via ethernet no routers will work( cant even access the router page when her ethernet is plugged in) When its unplugged everything works perfectly. Ive tried 3 different routers and they all cause the same problem. But heres the thing, if i use the ethernet cord in any other computer, there is no issues, as ive replaced the ethernet cord numerous times to check if that was the problem.
Sounds like some form of IP address conflict. It would be strange but if the pc for example has as its ip address and the router uses the same ip address. Hard to say check the setting on the ethernet nic on the pc and see what it is using.

It could also be something like malware or maybe their is a vpn misconfigured.

Just hooking up a ethernet cable should make no difference. Now if the pc has mulitple ethernet ports then you could have issues.
Sounds like a corporate vpn connection is messing up the local network. What I would suggest doing is putting her system in the dmz and see if that helps. Otherwise, change the ip subnet on your router from the default.