On Fri, 08 Jun 2007 15:03:42 -0400 Mike Schmidt <[EMAIL PROTECTED]> wrote:
> please cc me directly with any responses - I am not (yet) a member of this > mailing list. > > I just created 99 dummy network devices, and they all had different, > random-looking addresses. I recently searched though all the IANA/IEEE > documentation looking for a mechanism or policy to select local, virtual mac > addresses that could not interfere with real ones. But there seems to be no > clear concensus. Even the use of the 'local' bit seems to be inconsistent, I > saw registered OUIs in the AA:... (from memory) range, for example. > > I noticed that all the mac addresses assigned by the dummy driver have the > 'local' bit set. For those who are wondering, that's the second least > significant bit in the first digit of the mac address: so all addresses that > start with x2, x3, x6, x7, xA, xB, and xE, xF are 'local'. The last bit is > the multicast bit. > > In the 2.4 kernels, these devices all received a 00:00:00... mac address, > although this is declared incorrect in the RFCs I read. So, I was making my > own, somewhat arbitrarily. In 2.6, this seems to be solved. Can anyone tell > me what the algorithm/criteria are that allow the 2.6 kernels to set up > random mac addresses without conflicting with real devices? > I have searched the mailing list, but it's pretty hard to select for this > kind of information. > > Thanks very much. This is a great mailing list. It's been very responsive to > me so far. I thank you all. 1. Learn to read the kernel source. dummy gets its addresses from random_ether_addr() 2. Read the maintainers file, questions like this goto [EMAIL PROTECTED] -- Stephen Hemminger <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
