This is a very broad title, and will probably not help anyone except for me if this happens for me again. One day when I had to restart my KVM host, none of my guests had internet connection. The eth0 on the KVM host was attached to a bridge (br0) and that host had connectivity through the bridge. Here are some configs (which had not changed since it worked): # /etc/network/interfaces source /etc/network/interfaces....
Installation (No X11) # Install prerequirements (ignore virtinst if you have x11) sudo apt-get install qemu-kvm libvirt-bin virtinst sudo usermod -aG kvm $USER sudo usermod -aG libvirt $USER Creating a new host (i.e. guest) # NAME-OF-VHOST is whatever you want to call your virtual host # SIZE-IN-MB is how many MBs of RAM you want to give the new host # LOCATION is the location to install from, you can find locations by typing `man virt-install` # NAME-OF-DISK is what disk you want to provide to the vhost, e....