Switching to randomly generated hostnames
pgf at laptop.org
Wed May 2 11:00:41 EDT 2012
> On Wed, May 2, 2012 at 10:52 AM, Daniel Drake <dsd at laptop.org> wrote:
> > On Tue, May 1, 2012 at 4:49 PM, John Gilmore <gnu at toad.com> wrote:
> > >> Currently, XO hostnames are set on first boot in the following format:
> > >> xo-A-B-C
> > >> Where A, B and C are the last 3 bytes of the MAC address expressed in
> > hex.
> > >>
> > >> In Nicaragua we are seeing cases where XOs have no hostname set, both
> > >> on XO-1 and XO-1.5. On XO-1 this is presumably because libertas
> > >> usb8388 init was never 100% reliable, and on XO-1.5 its presumably
> > >> because the wireless card was DOA but was replaced after first boot.
> > >
> > > Why would we need to get it from the wireless card? Isn't the
> > > laptop's MAC address stored in the manufacturing data in motherboard
> > > flash?
> > Good point.
> I believe I've seen cases where the mfg data doesnt match the actual real
> MAC address. If memory serves, it's on the older 1.5's, presumably where
> the wireless module had been swapped out. If that is the case, it might
you're correct on both counts: that it may not match, and that it
probably won't matter.
> not matter, since the use case is that the old module was probably trashed
> and so the mfg data is still as unique as it needs to be. Also, I'm at
> work and don't have the old 1.5's in front of me right now, so I could be
> mistaken and the mfg data does get auto-magically updated when the module
> is switched. If so, sorry for the noise.
> > >> I propose we move to generating hostnames in the same format as before
> > >> (xo-A-B-C), but with A, B and C assigned as random hex digits on first
> > >> boot.
> > >> (If people are worried about collisions, maybe we add a D digit.)
> > >
> > > Existing hostnames have three bytes of info (e.g. xo-12-3a-49).
> > > Particularly if you're going to generate them at random rather than
> > > by prior assignment like MACs, why reduce the amount of unique
> > > information (e.g. xo-1-a-4 or xo-1-a-4-d)? Producing three random
> > > bytes of info for the hostname, rather than 1.5 or 2 bytes, would
> > > reduce the chance of collisions; and has the advantage of not
> > > changing either the size or format of the hostnames, in case
> > > anything else is depending on it.
> > You're right. When I wrote "hex digits" I actually meant to write "hex
> > bytes". i.e. I was not suggesting that we reduce the amount of data,
> > only change where it comes from.
> > Daniel
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paul fox, pgf at laptop.org
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