After 5 unsuccessful Arch Linux installations, I've got two that installed correctly. The first time, the network worked fine, and I was even installing it over SSH.
After booting from the installed system instead of the live CD, it can't connect to the network, I get the following message when I try to ping anything, even my router:
connect: Network is unreachable
I've tried installing Arch again, because nothing on the internet seemed to fix my issue. After installing, I'm getting the same issue.
It appears it's failing to start eth0 because it times out.