I have a router to which I have my desktop (running Ubuntu) connected via LAN & I use it on my phone via wifi. Sometimes it happen that the LAN one will stop working for no reason but the wifi will work fine. And it will resolve away by itself.

Since last night, the router was restarting again & again on its own, so I lodged a complaint about it and they said the router is faulty and will be replaced, but I know they don't know anything about how things work & is just going to shoot an arrow in the dark. These restarts has happened for the first time, LAN-wifi issue described earlier is a common one (but not frequent one).

So is the router faulty or there is some issue from my ISP side which will continue to persist even after they change the router? My very best guess is that they will replace it with an older refurbished router which will tend to give me more troubles in the coming time, so its better if I change it only its faulty (this is a new one - 6months old, I am its first hand user).

I am happy to provide any details.