Freddy Freeloader wrote:
The first time I run "/etc/init.d/networking restart" after a reboot I
get the same message I would if I ran "ifdown eth0" about eth0 releasing
its dhcp address, and I no longer have network connectivity, i.e. the
/etc/init.d/networking script does not seem to call ifup -a to restart
all network connections. (I have only one nic on this computer.) To
get network connectivity back I must manually run "ifup etho".
The problem is rooted in Bug#300937. It is about how to handle
hotplug network devices.
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=300937
The default Etch installation configures networking such as you are
seeing now. But let's back into it from the side. The configuration
is:
allow-hotplug eth0
You noted "ifup -a". But /etc/init.d/networking does call ifup -a.
But looking at the man page for ifup shows:
-a, --all
If given to ifup, affect all interfaces marked auto.
So 'ifup -a' only brings up interfaces marked auto but a default Etch
installation sets all interfaces to allow-hotplug. Now you can see
why restarting networking does not bring up networking.
And in the man page for interfaces it says:
Lines beginning with the word "auto" are used to identify the
physical interfaces to be brought up when ifup is run with the
-a option. (This option is used by the system boot scripts.)
...
Lines beginning with "allow-" are used to identify interfaces
that should be brought up automatically by various
subsytems. This may be done using a command such as "ifup
--allow=hotplug eth0 eth1", which will only bring up eth0 or
eth1 if it is listed in an "allow-hotplug" line.
My question is, is this behavior by design, or have I stumbled across a
bug?
I don't know the full history behind this but looking at the
Bug#300937 I assume the design is that network events are now moved
from boot time action to network event time action to support hotplug
network interfaces. Looking in /usr/share/doc/udev/README.Debian.gz I
see:
After receiving events about network interfaces, net.agent will call
ifupdown using the --allow=hotplug option. This makes the program act
only on interfaces marked with the "allow-hotplug" statement.
E.g: "allow-hotplug eth0" instead of the usual "auto eth0".
I have not researched further what it would take to trigger udev to
restart networking but I presume there is a path through it that would
do so. To return to the previous behavior you may change the
allow-hotplug stanzas into auto stanzas and then restarting networking
will restart the network interface. I would welcome further
information on this area.
Bob