For months I've been running 12.04 headless home server with a bridge connected through eth0. I've been using this /etc/network/interfaces
file:
auto lo iface lo inet loopback auto br0 iface br0 inet static address 192.168.8.1 netmask 255.255.255.0 network 192.168.8.0 broadcast 192.168.8.255 gateway 192.168.8.2 dns-nameservers 192.168.8.2 dns-search cluster.toy pre-up ip link set eth0 down pre-up brctl addbr br0 pre-up brctl addif br0 eth0 pre-up ip link set eth0 up post-down ip link set eth0 down post-down ip link set br0 down post-down brctl delif br0 eth0 post-down brctl delbr br0
However, after a weird network error I looked at my logs and saw that NetworkManager was repeatedly trying to bring up eth0, which it absolutely should not be doing (eth0 is a slave to br0, which is statically configured).
My understanding is that since I have NetworkManager.conf set with this setting:
[ifupdown] managed=false
It is supposed to ignore any interfaces mentioned in the /etc/network/interfaces
file. So I have some questions:
- Am I missing something, or is there a bug in NetworkManager that it doesn't parse bridge stanzas in
/etc/network/interfaces
correctly to know to ignore them? - Is there some sort of dummy statement I now have to put in
/etc/network/interfaces
to trick network manager into leaving it alone? - Alternatively, can I just
apt-get remove network-manager
with no negative consequences?
Best Answer
NetworkManager tries to manage eth0 because eth0 is not configured in /etc/network/interfaces.
To cause NetworkManager not to touch eth0, add the following stanza to /etc/network/interfaces.
iface eth0 inet manual
If you aren't using NetworkManager then you can safely remove network-manager.
By the way, there's an easier way to configure bridges in /e/n/i. Use the bridge_* options as illustrated in the answer by bodhi.zazen.