Re: LANANA: To Pending Device Number Registrants

Vojtech Pavlik
2001-05-16T08:02:48Z

On Tue, May 15, 2001 at 11:56:41PM -0700, Jonathan Lundell wrote:
> At 12:31 PM +1000 2001-05-16, Andrew Morton wrote:
> > > When I ifconfig one of a collection of interfaces, I'm very much
> >> talking about the specific physical interface connected via a
> > > specific physical cable to a specific physical switch port.
> >>
> >
> >Yes, it can be a security trap as well - physically move a card and
> >your firewall rules end up being applied to the wrong connection.
> >
> >The 2.4 kernel allows you to rename an interface. So you can build
> >a little database of (MAC address/name) pairs. Apply this after booting
> >and before bringing up the interfaces and everything has the name
> >you wanted, based on MAC address.
> >
> >Andi Kleen has an app which does this:
> >
> > ftp://ftp.firstfloor.org/pub/ak/smallsrc/nameif.c
> >
> >but apparently some additional kernel work is needed to make
> >this work 100% correctly. I do not know what the specific
> >problem is.
>
> There's a bit of a catch 22, though, if you don't have unique MAC
> addresses in the system (across multiple interfaces). It's common
> practice in the SPARC world (Solaris, anyway) for all the interfaces
> to default to a single system-wide MAC address. The fact that MAC
> addresses are at least semi-volatile is also bothersome.
>
> It's also true that some buses simply don't yield up physical
> locations (ISA springs to mind,

ISA is quite fine, you can use the i/o space as physical locations.

> and I gather that FC is squishy that
> way), but it's desirable to be able to make the connection all ways
> (eth# <-> bus location <-> physical location <-> MAC address) in a
> uniform manner. (Where MAC address might be something else in a
> non-Ethernet domain.)

Yes.

--
Vojtech Pavlik
SuSE Labs