Running networking configurator stops graphic apps launching (live CD)

[Robert Persson]

In the live CD, whenever I use the networking configurator I lose the ability to
launch applications that use X, either through Gnome or via a terminal. With
Gnome I get a spinning wheel for a while and then nothing happens. When I try
to launch the application from a console I get the message "Unable to connect to
X server".

I don't know exactly what it is in the networking configurator that causes this,
but what I have tried to do each time is to use the new network connection
wizard to start a new connection. In hindsight I think that the CD
auto-configurator may have correctly configured the network already, despite
signs to the contrary, so I may have tried to start the same connection twice
each time. However I would have to reboot again to check this, but it is dinner
time so I will have to leave that to you.

(However the fact that Ubuntu correctly configures my network connection is
good, because I have to manually "modprobe sk98lin" in Knoppix before I can get
networking.)

[Ricardo Pérez López (ricardo)]

I have the same problem here.

Anybody knows anything about this problem? I think this is a *serious* bug.

[Matt Zimmerman (mdz)]

Please do not change the severity or priority of bugs; these are used to
coordinate development work.

It sounds like perhaps something is changing the hostname of the system. It
would help if you could provide the exact error message that you see.

[Ricardo Pérez López (ricardo)]

(In reply to comment #2)
> Please do not change the severity or priority of bugs; these are used to
> coordinate development work.

Ok, sorry about that. I will not do it again :)

> It sounds like perhaps something is changing the hostname of the system. It
> would help if you could provide the exact error message that you see.

I write a question in ubuntuforums.org (see
http://www.ubuntuforums.org/showthread.php?t=2232), and I had got this response:

--------BEGIN----------
That happens when you change the hostname. X doesn't allow you to connect to the
server anymore because of the X security model. The following commands aren't
restricted to the live CD, use them to change the hostname without restarting a
running X server.

You must add the current magic cookie with the new hostname to your
Xauthorization list:

$ xauth -list oldhostname/unix:0 MIT-MAGIC-COOKIE-1 cookie
$ xauth add newhostname/unix:0 MIT-MAGIC-COOKIE-1 cookie

Replace newhostname with the new hostname and copy-paste the cookie from the
first output in the second command. The cookie is a MD5 encoded string.

Make sure /etc/hostname has the new hostname
and /etc/hosts has an alias for the new name to 127.0.0.1

When I tried the live CD I also ran across this problem,
I then chose to not change the hostname, just the dhclient config like this:
Fisrt I edited the /etc/network/interfaces file by hand with 'iface eth0 inet dhcp'
and enabled 'send host-name "blabla";' in /etc/dhcp3/dhclient.conf.
After 'ifup eth0' the cable modem was up and running.
--------END-----------

(Taken directly from the ubuntuforums.org response.)

I did not tested the solution yet, but I think this could be ok. The gnome
network configurator seems to change the hostname.

Thanks a lot, and sorry about my horrible English.

[Ricardo Pérez López (ricardo)]

> It sounds like perhaps something is changing the hostname of the system. It
> would help if you could provide the exact error message that you see.

I have got a * WORKAROUND * about this problem:

When I change the network configuration, using the gnome net configuration app,
I've observed that this changes automatically the hostname to 'macaroni' 8|

All we need to do is to change the hostname again to 'ubuntu', and all will work
since that.

Moreover, I've observed that, when the system boots, the /etc/hostname file
contains 'macaroni', and not 'ubuntu'. Maybe the solution is to write 'ubuntu'
into the file /etc/hostname, instead of 'macaroni'.

How do you look it?

[Ricardo Pérez López (ricardo)]

I don't know why this bug is not already resolved. The solution seems quite
simple: to change the hostname from "macaroni" to "ubuntu" in every place it is.
With that way, the "network-admin" utility will show the correct name. By now,
network-admin has the default name "macaroni" in General -> host name.

Where is the difficult matter with this bug?

[Andreas Mueller (amu)]

(In reply to comment #5)
> I don't know why this bug is not already resolved. The solution seems quite
> simple: to change the hostname from "macaroni" to "ubuntu" in every place it is.
> With that way, the "network-admin" utility will show the correct name. By now,
> network-admin has the default name "macaroni" in General -> host name.
>
> Where is the difficult matter with this bug?

There's no problem with it, it will be fixed with the next Release.

Cheers
amu

[Andreas Mueller (amu)]

This is now fixed. Thanks for reporting