I'm using Arch Linux. Last week I decided to install it on my desktop too (Windows 8 dual boot) but for some reasons it makes my router go crazy! I have set it up with Ethernet connection and here is the key: it works fine until you start a desktop environment.
I use GDM as my desktop manager and it does the job perfectly. I have GNOME, Cinnamon and XFCE installed. When you start ANY of these, LAN LEDs on the router start blinking like crazy and if you ping the router from another computer you'll notice it will at first respond slower and slower then it won't respond at all.
On the Arch PC, the internet keeps working.. but it's the only thing in the LAN who can actually reach the gateway.
What could be messing up my router like this? I'm not very familiar with desktop environment config files so I have yet to touch anything. I only disabled NetworkManager in Cinnamon (I got it running previously) thinking it might have been the cause, but the problem is still there.