On Wednesday 31 May 2006 21:05, Jeff Dike wrote: > On Tue, May 30, 2006 at 08:12:59PM +0200, Blaisorblade wrote: > > I've being thinking to this and I'm wondering why we shouldn't do it. > > When we have set no IP or 0.0.0.0, which is not a unique IP, and we bring > > it up, we should choose a random MAC to use. > > Conditions: the broadcast bit must be 0 and the "locally-assigned address > > flag" must be 1 (as likely we already do).
> Yeah, this sounds like a good idea. > > For which bits they are, I've a doubt. > > On Tanenbaum's book they're marked as the two most significant (leftmost) > > bits (broadcast being the most significant one), but since we've longly > > known the broadcast bit is the lowest-order one of the highest bit, I > > suspect that MACs are read in little-endian bit order (which likely > > implies the same for the whole packets). I can't verify this, but bytes > > in many fields are moved to be in network order i.e. big-endian order > > (MACs are always used in the network order). > So what is the second bit? I only know about the broadcast/multicast bit, > and no one has bothered clueing me in on any other special bits :-) Look at the other answer (which points to include/linux/etherdevice.h: random_ether_addr()) for the bit position - the code pointed out shows that indeed bit are reversed from the "text-book order". For the "locally assigned", I guess that means we'll never conflict with a MAC set on some NIC. -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com ------------------------------------------------------- All the advantages of Linux Managed Hosting--Without the Cost and Risk! Fully trained technicians. The highest number of Red Hat certifications in the hosting industry. Fanatical Support. Click to learn more http://sel.as-us.falkag.net/sel?cmd=lnk&kid=107521&bid=248729&dat=121642 _______________________________________________ User-mode-linux-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
