I've had Ubuntu 12.04 on a server for the last several months, with everything working fine. Last night I did an aptitude update && aptitude safe-upgrade to bring in all the latest security changes, and now when I boot the server no lo device is created.
It brings up the physical ethernet interfaces correctly, and I can ping in and out of the machine on those interfaces, but nothing can connect to anything on either localhost or 127.0.0.1.
ifconfig lists only eth0 and eth1. No lo at all.
Here are the contents of /etc/network/interfaces:
# The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 #NetworkManager#iface eth0 inet dhcp
Where should I be looking to diagnose and fix?