Network manager gone - eth renamed, can't load config
I thought I had successfully bonded two nic cards but then, started getting the message "Waiting for network configuration" and "waiting up to 60 more seconds for network configuration" and then it boots without network configuration.
I'm running edubuntu 12.04 with an LTSP network.
While struggling to get the nic cards bonded I saw some warnings to deactivate the Network Manager but it seemed to vanish on its own. The "two arrow icon" in the nav bar that starts the manager disappeared but everything still seemed to work. I had internet anyway, and was working on getting the clients to connect via dhcp. The last change I made was to etc/default/isc-dhcp-server where I changed the INTERFACES setting to "bond0" (and then the clients were able to boot into the LTSP server). At the next reboot, however, everything was broke again.
What the command line lshw revealed was that the one of the three nic cards that faces the internet (the onboard nic card) had been renamed from eth0 to eth3. Nothing I've tried in the etc/network/interfaces file or in the etc/udev/rules.d/70-persistent-net.rules file makes any difference. There is no "eth3" config in either of those files (only eth0, eth1, and eth2).
So, can anyone help with where the system is renaming eth0 to eth3?
But, back to NetworkManager, looking at etc/NetworkManger/Netwrokmanager.conf I remember changing [ifupdown] managed to "true" way, way back when I first installed the server but some frum post said that turned NetworkManager "off". So I am in a state of confusion about bthe whole NewtworkManager issue, whether it should be on or off when bonding nic cards etc and whether it is related to the current problem of renaming the eth names.
Thanks in advance for any help you can lend.