network manager has gone crazy

[Marko Vojinovic]

On Tue, 13 Nov 2012 20:44:04 +0100 lee <lee at yun.yagibdah.de> wrote:
> Tim <ignored_mailbox at yahoo.com.au> writes:
> > There does appear to be some NetworkManager interface through the
> > command line.  Dunno whether it's going to be of any use to you,
> > though.
> 
> Hm I didn't find out what it is yet.

man nmcli
man nm-tool
man nm-online
man NetworkManager
man NetworkManager.conf

If you prefer a GUI to control NetworkManager, you probably want to

  yum install NetworkManager-gnome

and start nm-applet utility, which should land in your
system-tray/dock/whatever, and from where you can do everything else.

> > As may have been pointed out in this thread, but definitely in the
> > past, NetworkManager is probably not be suitable for servers.  It
> > is geared towards having something else configure your network,
> > usually a server is self-configured, or at least the central server
> > is (the one everything else relies on).
> 
> It's a very strange idea that something else should configure the
> network.

Why do you consider such a scenario to be strange? The dhcp was
invented for precisely this purpose. It is widely used on laptops and
other mobile devices, in home&office environments for desktops, etc.

Typically only servers need to have a static IP. And even that can be
remote-configured by the dhcp server. In fact, the dhcp server itself
is the only one requiring a static manually-configured IP. Everything
else can be configured by a remote dhcp server.

> Anyway, I still want to know, even with networkmanager disabled.  It
> doesn't hurt to learn something new :)
> 
> > I have to admit I'm intrigued to find out what would happen if you
> > ran a DHCP server on a machine with NetworkManager handling the
> > network interfaces.  But not sufficiently to try it out, at 2:30 in
> > the morning.
> 
> It probably won't work because there won't be any network interfaces
> configured the DHCP server could use to receive broadcasts and send
> answers so that networkmanager could configure such interfaces.

The dhcp server requires a NIC with a static IP (it cannot serve
itself). If NetworkManager is configured so that it assigns a static IP
to that particular interface, dhcp will be happy, and everything will
work well.

It can even serve the IPs for other NICs on the same machine (if any
are present), and NetworkManager will pick those up and configure
them, if they are set up to use dhcp... ;-)

> > Regarding trying to find its configuration files, I would have tried
> > something like:  locate -i networkmanager |grep etc

I doubt that in normal circumstances one would ever need to manually
edit files in /etc/NetworkManager/. All configuration files that are
related to the actual network interfaces (used by NM) are
in /etc/sysconfig/network-scripts/, among which the most interesting
are the ifcfg-* files. Those are probably the only files that one could
be motivated to hand-edit. At least in normal circumstances, and in
the absence of a GUI utility.

HTH, :-)
Marko