CentOS - Apr 2015 - Prevent network setup from changing the hostname

How can I block network setup (via NetworkManager) from changing
the machine's hostname whenever the network configuration changes?

The problem: When my graphical login session starts, the xauth
database gets an token that is labeled with the hostname at that
time. If there is not yet a network connection, that will be
"localhost.localdomain". When a network connection is then made
(my wireless connection needs the key from my login), the hostname
changes. That breaks X session sharing because there is no xauth
token that matches the current hostname. If I get a root shell
with "su -", commands launched from that shell cannot access the
display. If I set up an ssh connection with "ssh -X", I get a
complaint about missing xauth data.

On systems with an "ONBOOT=yes" network connection, there is no
problem since the hostname is set before the X session starts.
It's just when the hostname changes during the X session that
there is a problem.

I am running CentOS 6, fully updated. It's taken me a long time
to track down the root cause of this problem. Now I just need a
solution, preferably something less ham-fisted than "xhost -".

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.

Make it a system connection instead of a user connection. Or give the
host a static name on install and don't allow dhcp to override it.

On 04/26/2015 07:26 PM, Robert Nichols wrote:
> How can I block network setup (via NetworkManager) from changing
> the machine's hostname whenever the network configuration changes?
>
> The problem: When my graphical login session starts, the xauth
> database gets an token that is labeled with the hostname at that
> time. If there is not yet a network connection, that will be
> "localhost.localdomain". When a network connection is then made
> (my wireless connection needs the key from my login), the hostname
> changes. That breaks X session sharing because there is no xauth
> token that matches the current hostname. If I get a root shell
> with "su -", commands launched from that shell cannot access the
> display. If I set up an ssh connection with "ssh -X", I get a
> complaint about missing xauth data.
>
> On systems with an "ONBOOT=yes" network connection, there is no
> problem since the hostname is set before the X session starts.
> It's just when the hostname changes during the X session that
> there is a problem.
>
> I am running CentOS 6, fully updated. It's taken me a long time
> to track down the root cause of this problem. Now I just need a
> solution, preferably something less ham-fisted than "xhost -".
>

-- 
Regards
  Peter Larsen

On 04/26/2015 06:31 PM, Peter Larsen wrote:
> On 04/26/2015 07:26 PM, Robert Nichols wrote:
>> How can I block network setup (via NetworkManager) from changing
>> the machine's hostname whenever the network configuration changes?
>
> Make it a system connection instead of a user connection. Or give the
> host a static name on install and don't allow dhcp to override it.
Making my wireless connection a system connection increases the
exposure of my WPA key and doesn't solve the problem of the network
configuration changing, perhaps because I connected or disconnected
an ethernet cable or the machine went to sleep on one WLAN and woke
up on another.

Do you know of a place I can set a static name that NetworkManager
won't override?  That would be ideal.  I just doesn't make sense
that the machine's internal relationships would depend on its
external connections.

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.