Re: [v6ops] Discussion of draft-ietf-v6ops-ula-usage-recommendations

Mark Smith <> Wed, 22 July 2015 03:32 UTC

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From: Mark Smith <>
Date: Wed, 22 Jul 2015 13:31:22 +1000
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To: Alexandru Petrescu <>
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Subject: Re: [v6ops] Discussion of draft-ietf-v6ops-ula-usage-recommendations
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On 22 July 2015 at 00:18, Alexandru Petrescu
<> wrote:
> 1. Brian suggested to recommend that globals should be there on the
> machines having ULAs as well, if I understand correctly.
> But I think so only on some Hosts, mainly the Hosts of end users.
> 2. the ULA RFC suggests a ULA prefix can be generated out of a MAC
> address.  That sixxs implementation does it.  Except it takes it too
> serious: it does not accept a MAC address which is not a real MAC
> address - in that oui.txt.  And random MAC addresses (for privacy)
> certainly are not in that oui.txt.
> I think this is an undesirable situation to be in: unable to generate
> ULAs because the only tool out there (sixxs) can't refuses a copy paste
> a MAC address from the widely used windows 7 laptops.

sixxs is not the only ULA generator out there.

Here's 4 others that showed up when I did a search for "ula generator"

I'm using random local MAC addresses on all of this host's interfaces,
yet a number of the above links generated an automatic ULA prefix for
me without issue (and I can't tell if they're IPv6 accessible and
might have used my IPv6 IID as a MAC address after removing FF:FE

> I am not sure what the problem is, but it's very good to have a very
> easy way to generate ULAs.
> 3. in an enterprise deployment there was a problem of ULAs deployed in a
> intra-network and another ULA space in another intra-network, of the
> same enterprise.  So we wanted to make sure two things: the two ULA
> spaces are distinct, or otherwise make sure the gateway router does not
> route between the two intranets' ULAs (but yes, route between their
> respective GUAs).   I am not sure how to translate that into advice,
> because I am not sure how it will unfold in the near future.

RFC4193 recommends that by default ULA addressed packets and routes
are not leaked outside of the ULA /48 assigned site.

> Alex
> Le 21/07/2015 16:02, Fred Baker (fred) a écrit :
> "Considerations For Using Unique Local Addresses", Bing Liu, Sheng
>> Jiang, 2015-05-03
>> This draft came up from the floor this afternoon. I think we need
>> some concentrated constructive conversation regarding it - we have
>> had a lot of the other kind.
>> What issues do we need to address to complete it. and what specific
>> recommendations would that include?
>> _______________________________________________ v6ops mailing list
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