On Wed, 03 Mar 2021 16:15:10 +0000
g4sra via Dng <dng@???> wrote:

> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> On Wednesday, March 3, 2021 3:21 PM, tito via Dng
> <dng@???> wrote:
>
> > On Wed, 03 Mar 2021 14:52:57 +0000
> > g4sra via Dng dng@??? wrote:
> >
>
> > > <-- huge snip -->
> > > Just for completeness should someone dig this thread up trying to
> > > solve an issue...such as a 12 port router....
> > > The kernel's FDT determines the order of detection for built-in
> > > interfaces. Learn how to make them, then don't change it and the
> > > interfaces will always come up the same way.
> >
>
> > Hi,
> > Cannot confirm that as I have a board with 8 onboard ports
> >
>
> > 00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection
> > (2) I219-LM (rev 31) 09:00.0 Ethernet controller: Intel Corporation
> > I211 Gigabit Network Connection (rev 03) 0a:00.0 Ethernet
> > controller: Intel Corporation I211 Gigabit Network Connection (rev
> > 03) 0b:00.0 Ethernet controller: Intel Corporation I211 Gigabit
> > Network Connection (rev 03) 0c:00.0 Ethernet controller: Intel
> > Corporation I211 Gigabit Network Connection (rev 03) 0d:00.0
> > Ethernet controller: Intel Corporation I211 Gigabit Network
> > Connection (rev 03) 0e:00.0 Ethernet controller: Intel Corporation
> > I211 Gigabit Network Connection (rev 03) 0f:00.0 Ethernet
> > controller: Intel Corporation I211 Gigabit Network Connection (rev
> > 03)
> >
>
> > and they used to come up in all possible permutations.
> > When I added a 4 port addon card
> >
>
> > 07:00.0 Ethernet controller: Intel Corporation 82576 Gigabit
> > Network Connection (rev 01) 07:00.1 Ethernet controller: Intel
> > Corporation 82576 Gigabit Network Connection (rev 01) 08:00.0
> > Ethernet controller: Intel Corporation 82576 Gigabit Network
> > Connection (rev 01) 08:00.1 Ethernet controller: Intel Corporation
> > 82576 Gigabit Network Connection (rev 01)
> >
>
> > things got even more funny.
> >
>
> > > Mask (delete, override with empty) e/udev rules and scripts and
> > > use the purpose created 'ifrename' utility. And don't use SystemD
> > > OS..
> >
>
> > eudev could do nothing because the names I would have liked where
> > in use same for ifrename.
> Correct, you can clearly not have more than one interface per name.
>
>
>
> > It works eventually if you use so called predictable new names
> > and rename to old style names but even then you cannot be sure the
> > predictable names will stay the same at next reboot.
>
> Your 'predictable' names name are being assigned by what ?

By the kernel, I suppose as you can pass a kernel command line
parameter with grub (net.ifnames=0 or net.ifnames=1)
to switch between eth* and en* names.

> > The only working solution is to:
> >
>
> > 1. at boot rename all detected interfaces to some temporary name
> > (e.g. eth*renamed) 2. rename eth*renamed to eth{0-99} by a
> > hardcoded list of mac addresses in the wanted order.
> >
>
> > 3. don't use udev it will not work (e.g delete
> > 70-net-persistent-names.rules) 4. eventually recreate
> > 70-net-persistent-names.rules on the fly at boot after having
> > renamed the interfaces with the desired names linked to mac
> > addresses.
>
> > 5. make sure 70-net-persistent-names.rules is DELETED at reboot
> > (or is on volatile storage) or chances will be good that you will
> > be locked out of your box at the next reboot.
>
>
> I believe that is exactly what I just previously posted, 'ifrename'
> does all the heavy lifting for you. No need to write scripts, parse
> the /sys filesystem, simply create '/etc/iftab', mapping each MACAddr
> to the name you wish to assign. That is the only downside, you need
> to know some prior piece of hardware information to create the
> mapping table.

I was there, I did try hard, but I was not able to make ifrename
work reliably in the case you want to rename and reorder
the interfaces (that is change the name and the number)
because you change it one by one but the names you want
are already in use by other interfaces that are up.

Ciao
Tito

> https://www.unix.com/man-page/debian/8/ifrename/
>
> https://www.unix.com/man-page/debian/5/IFTAB/
>

> >     Ciao,
> >     Tito

>
>