Ubuntu
network-manager package

NetworkManager fails to configure wlan0 when /e/n/i contains "iface eth0 inet manual"

Bug #678450 reported by Magnus Ihse Bursie
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This bug affects 1 person
Affects Status Importance Assigned to Milestone
network-manager (Ubuntu)
New
Undecided
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Bug Description

Binary package hint: network-manager

I install Maverick (10.10) on a new computer. I boot it, and I don't get any network connectivity on the very first start. That is no good way of starting a new installation...

What seems to have happend is this:
In /etc/network/interfaces, apart from the loopback stanza, the following is added:
auto eth0
iface eth0 inet manual

Combined with /etc/NetworkManager/nm-system-settings.conf containing:
[ifupdown]
managed=false

this effectively means that NetworkManager does not "see" eth0. For some reason, this seems to prevent the GNOME Network Manager applet to appear, even though I have a wireless card as well (which shows up in the NM applet after I fixed the eth0 problem).

This has happened on at least four computers, one desktop and one laptop, and also a co-worker on his laptop, and finally on a virtual installation in VirtualBox (to test this behaviour again). The co-worker found out one workaround, by changing the NM config file to "managed=true". I tried to remove the eth0 part of /etc/network/interfaces, which worked as well. Comparing with older versions of Ubuntu, which has managed=false but no eth0 information in interfaces, this seems like the preferrable fix.

There seems to be several issues at work here.

First of all, why did I get the eth0 stuff in my interfaces file during installation? (The major problem)
Second, why did this stop Network Manager from managing my wifi card?

I am happy to provide whatever extra information is needed to solve the bug.

All of these computers were connected on a company network which requires a proxy to connect to the outside world. I don't know if it is relevant, but it might be. Also, several people here (including me) have been using Ubuntu for a long time on this network, and this has never happened before, on anything between Jaunty and Lucid. And yes, we do have a DHCP server on the network.

Revision history for this message
Magnus Ihse Bursie (ihse) wrote :

When explicitely running "sudo dhclient" in a terminal from the live cd, dhclient hangs after:
DHCPREQUEST of ... on eth0 to 255.255.255.255 port 67
DHCPACK of ... from ...

This might or might not be related.

Revision history for this message
Magnus Ihse Bursie (ihse) wrote :

It turns out that question number one (why the eth0 stuff ended up in /etc/network/interfaces) was already covered by bug 388060 (an issue with casper).

As for the second issue however, about the valid interface (a wifi card) not showing, it still seems a valid problem. Some more digging around turned up that by using nm-tool, I could still see the wlan0 card. So this is either a problem solely in nm-applet, or in the combination of NetworkManager and nm-applet.

I will attach the output of nm-tool and nm-applet.

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Magnus Ihse Bursie (ihse) wrote :
Revision history for this message
Magnus Ihse Bursie (ihse) wrote :
Revision history for this message
Mathieu Trudel-Lapierre (cyphermox) wrote :

Fair enough. Both the workarounds listed there are the right way to do it, and it does seem like this is an issue with casper, which however has logic to handle the case of NetworkManager, even though it doesn't quite work properly. I will check whether it really still applies and look for a fix ;)

Marking as High following the logic in bug 388060.

Revision history for this message
Mathieu Trudel-Lapierre (cyphermox) wrote :

As a workaround to make the install more streamlined, you could use a late_command script in the preseed to handle cleaning up /etc/network/interfaces.

Revision history for this message
Thomas Hood (jdthood) wrote :

ihse (the submitter) wrote:
> As for the second issue however, about the valid interface
> (a wifi card) not showing, it still seems a valid problem.
> Some more digging around turned up that by using nm-tool,
> I could still see the wlan0 card. So this is either a problem
> solely in nm-applet, or in the combination of
> NetworkManager and nm-applet.

Is this still a problem in Precise?

Mathieu wrote:
> Marking as High

Importance is still Undecided.

summary: - Network connection fails on fresh install
+ NetworkManager fails to configure wlan0 when /e/n/i contains "iface eth0
+ inet manual"
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