RE: [PATCH v6] r8152: Add support for setting pass through MAC address on RTL8153-AD

From: Mario_Limonciello
Date: Tue Jun 14 2016 - 13:58:11 EST


> -----Original Message-----
> From: Andrew Lunn [mailto:andrew@xxxxxxx]
> Sent: Tuesday, June 14, 2016 12:23 PM
> To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>
> Cc: pali.rohar@xxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx;
> davem@xxxxxxxxxxxxx; hayeswang@xxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> usb@xxxxxxxxxxxxxxx; anthony.wong@xxxxxxxxxxxxx
> Subject: Re: [PATCH v6] r8152: Add support for setting pass through MAC
> address on RTL8153-AD
>
> > > It is same, how to handle two network cards which tell us, that they
> > > have same MAC addresses.
> > >
> >
> > The kernel handles this just fine. In doing this patch I checked to see
> > what it does in that scenario. Two devices are made. systemd doesn't
> > rename the second device via the MAC name (eg enxAABBCCDDEEFF).
>
> What does you dhcp server do? Does it gives out the same IP address?
> You then have two interfaces on the same network, with the same MAC
> address and IP address. Then what happens?
>
> Andrew

I didn't test it on the same network, I used two separate networks.

I expect that the DHCP server would be awfully confused and you'd
run down an interesting problem path if it got the same MAC twice.