My card: # lspci | grep -i ethernet Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 03) After doing pacman -Syu, ethernet on my desktop stopped working. The card on my laptop is the same, at least according to lspci, and is working fine. When I upgraded, there was a change in syntax in rc.conf for defining the network, but I'm just attempting dhcp for now before I try to set up a static ip: interface=eth0 address= netmask= gateway= I've tried resetting the router and switching from the kernel's r8169 driver to the r8168 driver from the aur. I compiled the aur driver on my laptop and transferred to the desktop on usb -- as long as they're both x86_64, this shouldn't be a problem, right? Regardless of my choice of driver, ethernet on the laptop works fine, and doesn't work at all on the desktop. If I set up ethernet manually using ifconfig to define the address/netmask/broadcast/etc (making sure the routes are correct), everything appears to work fine until I try to ping the router and get "Destination Host Unreachable". And the kicker is that the light on the router for the port I have my ethernet cable plugged into will light up for the laptop, but not the desktop. Given this and the other behavior, I'm inclined to think it's a hardware issue, but this hardware is only several months old, and having this happen right after an upgrade seems unlikely to be a coincidence. Anything else I can try short of reinstalling or getting a replacement from the manufacturer?