There are plenty of good reasons for a technical person to get pissed on all these and start cursing while trying to figure out how to stop the Network Manager network-manager overwriting /etc/network/interfaces and stop resolvconf overwriting /etc/resolv.conf.
Why do I want to make /etc/network/interfaces and /etc/resolv.conf stick? Well, if you don't get it there is no reason explaining it.
To disable network-manager -- Make /etc/network/interfaces stick.
$sudo -s #stop network-manager #echo "manual" > /etc/init/network-manager.override
To disable resolvconf -- Make /etc/resolv.conf stick --
I ended up not disabling it ( just in case )
In Ubuntu 12.04 /etc/resolv.conf is just a symlink so it would be easy to change it /etc/resolv.conf to a regular file or change /sbin/resolvconf
If you disable network-manager you could just use /etc/resolvconf/resolv.conf.d/base as your /etc/resolv.conf and leave resolvconf alone.
# cat /etc/resolvconf/resolv.conf.d/base nameserver 10.1.2.12 nameserver 10.1.2.13
Make /etc/network/interfaces and /etc/resolv.conf stick on ubuntu 12.04 LTS desktop