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Groups > comp.os.linux.networking > #4045

Re: Fixed IP addreses on network.

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Le 03/04/2017 à 02:07, William Unruh a écrit :
> On 2017-04-02, Jerry Peters <jerry@example.invalid> wrote:
>> Pascal Hambourg <pascal@plouf.fr.eu.org> wrote:
>>> Le 01/04/2017 à 12:50, Carlos E. R. a écrit :
>>>> On 2017-04-01 09:41, Pascal Hambourg wrote:
>>>>> Le 01/04/2017 à 02:01, Carlos E. R. a écrit :
>>>>>>
>>>>>> "The classic naming scheme for network interfaces applied by the kernel
>>>>>> is to simply assign names beginning with "eth0", "eth1", ... to all
>>>>>> interfaces as they are probed by the drivers. As the driver probing is
>>>>>> generally not predictable for modern technology
>>>>>
>>>>> "Modern technology" actually standing for "systemd/udev".
>>>>
>>>> No, it means the kernel.
>>>
>>> No, the kernel behaviour has not changed in this matter.
>>>
>>>>> Actually the problem comes from the asynchronous way "modern technology"
>>>>> probes hardware and loads drivers.
>>>>
>>>> Yes, in the kernel.
>>>
>>> No, the kernel is not responsible for loading modules asynchronously.
>>> Udev is.
>>>
>>>>> I beg to differ. I have perfectly stable kernel-defined interface names
>>>>> on a machine *not* running udev.
>>>>
>>>> Chance. Or old kernel.
>>>
>>> Chance has nothing to do with this.
>>> Rather old kernel (3.2.x), but a newer one would behave exactly the same.
>>
>> And does, I'm using 4.10.6 on at least one machine and getting *eth0*
>> as the net device name. Salix (Slackware) 14.1 so no systemd.
>> Fortunately Pat hasn't bought into the systemd insanity for slack.
>
> On mageia cauldron during the boot sequence I get the line
> ath10k_pci 0000:3a:00.0 wlp58s0: renamed from wlan0
> so the kernel names it wlan0, and ath10k_pci module then renames it.
> Is the module part of the kernel?

Yes, it is a kernel module and as such it is a part of the kernel. 
ath10k_pci is the kernel driver for your Qualcomm/Atheros wireless 
network device. Actually it is the kernel driver which assigns the 
initial interface name (wlan0), so the message is a bit puzzling.

On my Debian Wheezy (oldstable, kernel 3.2) and Jessie (stable, kernel 
3.16), the kernel message say that the network interfaces are renamed by 
udevd or systemd-udevd. Wheezy does not have systemd, and Jessie has an 
old version of systemd which does not assign predictable network 
interface names.

So I did a bit of testing with more recent versions from Debian Stretch 
(testing) of kernel (4.9, is that new enough ?) and systemd which 
assigns predictable interface names.

Here are the results :

Linux 3.16 + old systemd : message from systemd-udevd, interface renamed 
with the old scheme eth*.

Linux 4.9 + new systemd : message from the kernel driver, interface 
renamed with the new scheme enp*s*.

Linux 4.9 + old systemd : message from systemd-udevd, interface renamed 
with the old scheme eth*.

Linux 3.16 + new systemd : no message, interface renamed with the new 
scheme enp0s*.

Linux 4.9 + new systemd but udev stopped (*) : no message, interface not 
renamed keeping its initial name eth*.

(*) Make sure not only systemd-udevd.service but also 
systemd-udevd-kernel.socket is stopped, otherwise the latter restarts 
the former on events such as module loading or device discovery.

 From these results it seems clear to me that :
- the renaming scheme depends on the version of systemd, not on the 
kernel version ;
- without udevd the kernel or kernel module just assigns an initial 
interface name as usual and does not rename network interfaces on its own ;
- the kernel behaviour is globally the same regarless of its version. 
The only change is the rename message source in the kernel log.

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Thread

Fixed IP addreses on network. Doug  Laidlaw  <laidlaws@hotkey.net.au> - 2017-03-30 03:23 +1100
  Re: Fixed IP addreses on network. Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-03-29 20:57 +0200
    Re: Fixed IP addreses on network. Doug Laidlaw <laidlaws@hotkey.net.au> - 2017-03-30 06:20 +1100
  Re: Fixed IP addreses on network. William Unruh <unruh@invalid.ca> - 2017-03-29 21:01 +0000
    Re: Fixed IP addreses on network. Doug Laidlaw <laidlaws@hotkey.net.au> - 2017-03-30 23:32 +1100
      Re: Fixed IP addreses on network. Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-03-30 20:28 +0200
      Re: Fixed IP addreses on network. Gordon <Gordon@clear.net.nz> - 2017-03-31 05:23 +0000
  Re: Fixed IP addreses on network. robert.wolfe@wildcat.uuhec.net (Robert Wolfe) - 2017-03-30 13:27 +0000
  Re: Fixed IP addreses on network. robert.wolfe@wildcat.uuhec.net (Robert Wolfe) - 2017-03-30 13:28 +0000
    Re: Fixed IP addreses on network. Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-03-30 20:34 +0200
      Re: Fixed IP addreses on network. Richard Kettlewell <invalid@invalid.invalid> - 2017-03-30 20:20 +0100
        Re: Fixed IP addreses on network. Gordon <Gordon@clear.net.nz> - 2017-03-31 05:44 +0000
      Re: Fixed IP addreses on network. "Jonathan N. Little" <lws4art@gmail.com> - 2017-03-30 16:56 -0400
        Re: Fixed IP addreses on network. Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-03-31 00:18 +0200
          Re: Fixed IP addreses on network. "Jonathan N. Little" <lws4art@gmail.com> - 2017-03-30 18:52 -0400
            Re: Fixed IP addreses on network. Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-03-31 19:38 +0200
  Re: Fixed IP addreses on network. ray carter <ray@zianet.com> - 2017-03-30 14:04 +0000
  Re: Fixed IP addreses on network. "Jonathan N. Little" <lws4art@gmail.com> - 2017-03-30 12:33 -0400
    Re: Fixed IP addreses on network. "Carlos E. R." <robin_listas@es.invalid> - 2017-03-31 01:59 +0200
      Re: Fixed IP addreses on network. "Jonathan N. Little" <lws4art@gmail.com> - 2017-03-30 23:10 -0400
        Re: Fixed IP addreses on network. Gordon <Gordon@clear.net.nz> - 2017-03-31 05:34 +0000
          Re: Fixed IP addreses on network. "Jonathan N. Little" <lws4art@gmail.com> - 2017-03-31 08:43 -0400
          Re: Fixed IP addreses on network. Jorgen Grahn <grahn+nntp@snipabacken.se> - 2017-03-31 14:10 +0000
            Re: Fixed IP addreses on network. "Jonathan N. Little" <lws4art@gmail.com> - 2017-03-31 11:02 -0400
            Re: Fixed IP addreses on network. Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-03-31 19:45 +0200
        Re: Fixed IP addreses on network. "Carlos E. R." <robin_listas@es.invalid> - 2017-04-01 02:01 +0200
          Re: Fixed IP addreses on network. Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-04-01 09:41 +0200
            Re: Fixed IP addreses on network. "Carlos E. R." <robin_listas@es.invalid> - 2017-04-01 12:50 +0200
              Re: Fixed IP addreses on network. Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-04-02 00:17 +0200
                Re: Fixed IP addreses on network. "Carlos E. R." <robin_listas@es.invalid> - 2017-04-02 01:22 +0200
                Re: Fixed IP addreses on network. Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-04-02 11:41 +0200
                Re: Fixed IP addreses on network. Jerry Peters <jerry@example.invalid> - 2017-04-02 20:00 +0000
                Re: Fixed IP addreses on network. Jerry Peters <jerry@example.invalid> - 2017-04-02 19:57 +0000
                Re: Fixed IP addreses on network. William Unruh <unruh@invalid.ca> - 2017-04-03 00:07 +0000
                Re: Fixed IP addreses on network. Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-04-06 23:58 +0200
  Re: Fixed IP addreses on network. John Carter <me@mymailsvr.org> - 2017-03-31 04:51 +0000
  Re: Fixed IP addreses on network. Dave <noone$$@llondel.org> - 2017-04-02 14:39 -0700

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