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

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.

On Sun, 26 Apr 2015 19:25:27 -0500
Robert Nichols wrote:
> Do you know of a place I can set a static name that NetworkManager
> won't override?  
What about this:

hostnamectl set-hostname whateveryouwant

-- 
MELVILLE THEATRE ~ Real D 3D Digital Cinema ~ www.melvilletheatre.com

On 04/26/2015 08:25 PM, Robert Nichols wrote:
> 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.
>
If you move networks and you are slaving your hostname to the DHCP
offered name, then yes. But why do that?  In /etc/dhcp/dhclient.conf you
can configure exactly what you want and don't want from the server. 
There's a lot of options (man dhclient.conf is very helpful) but here's
an example:

send dhcp-client-identifier = hardware;
request subnet-mask, broadcast-address, time-offset, routers,
                domain-search, domain-name, domain-name-servers, host-name;

Just take out the host-name and you won't get (a new) one. You should
however make sure that all your servers have a hostname configured
before you do that. /etc/sysconfig/network is where you do that on CentOS6.
> 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.
So your key isn't visible and only root can change a system device.  A
system device gets activated before the desktop. So you're not depending
on having access to gconf etc.
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/sec-User_and_System_Connections.html
>
> 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.
>
See above. It's standard dhclient options.

-- 
Regards
  Peter Larsen

On 04/26/2015 07:37 PM, Frank Cox wrote:
> On Sun, 26 Apr 2015 19:25:27 -0500
> Robert Nichols wrote:
>
>> Do you know of a place I can set a static name that NetworkManager
>> won't override?
>
> What about this:
>
> hostnamectl set-hostname whateveryouwant
# which hostnamectl
/usr/bin/which: no hostnamectl in 
(/usr/lib64/qt-3.3/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin)
# yum provides \*/hostnamectl
   '''
No Matches found

Apparently does not exist for CentOS 6.

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

On 04/26/2015 07:57 PM, Peter Larsen wrote:
> On 04/26/2015 08:25 PM, Robert Nichols wrote:
>> 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.
>>
>
> If you move networks and you are slaving your hostname to the DHCP
> offered name, then yes. But why do that?  In /etc/dhcp/dhclient.conf you
> can configure exactly what you want and don't want from the server.
> There's a lot of options (man dhclient.conf is very helpful) but
here's
> an example:
NetworkManager invokes dhclient with a generated config file that
ignores /etc/dhcp/dhclient.conf:

      dhclient ... -cf /var/run/nm-dhclient-wlan0.conf ...

I ran across another report that suggests setting HOSTNAME to
something other than "localhost.localdomain" in
/etc/sysconfig/network would fix the problem.  For the moment,
that seems to be working.

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