RedHat /Implicit/default connection(s)

[Thomas Haller]

Hi,

On Fri, 2024-04-26 at 12:12 +0200, Thomas HUMMEL wrote:
> 
> 
> On 4/26/24 10:14, Thomas Haller wrote:
> 
> > Profiles always exist on disk. See `nmcli -f all connections`. See
> > also
> > /{usr/lib,run}/NetworkManager/system-connections
> 
> Hello, thanks for your reply. I didn't know that I (wrongfully)
> thought 
> some connections could be transient in ram only (until one decide to 
> save them on disk).

/run is a tmpfs, so that is "in ram only".

Except,
- you also them like regular files on disk
- they survive a service restart (but not a reboot)


> 
> You're correct: Wired comes from initrd and System enp33s0f0 comes
> from 
> network-scripts/ifcfg-enp33s0f0. And I indeed confued Wired with
> Wired #n.
> 
> Now I have to understand what created this file as I don't see it 
> neither in the image I boot.
> 
> Could it be the following scenario :
> 
> NM manages anything that is not explicitly set unmanaged

that's true, by default all devices are managed. Of course, you could
invert that with `[device].managed=0` in NetworkManager.conf.

If a device is unmanaged, you see "unmanaged" state in `nmcli device`.
In that case, NM should not do anything whatsoever with this device.

> and without any 
> initial profile (neither in network-scripts nor system-connections)
> uses 
> its internal dhclient-like component and creates this ifcf-enp33s0f0
> ?

I don't think that NM automatically would create such an ifcfg file. It
would then be called "ifcf-Wired connection 1".


> 
> Sorry for those naive basic questions I just never asked myself
> although 
> I did dig deep into some other sides of NetworkManager...
> 
> Note than at this stage I'm not 100% sure my provisionning software 
> don't create this in some postbootscript but I doubt it

Check the syslog/journal. NetworkManager should log when it creates a
profile. If the profile exists before NetworkManager starts, then you
know something else create it. Possibly enable `level=TRACE`. See
DEBUGGING in `man NetworkManager`.


Thomas