Re: [homenet] Updating DNS [was: How many people have installed the homenet code?]

"Ray Hunter (v6ops)" <> Thu, 12 May 2016 13:41 UTC

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Date: Thu, 12 May 2016 15:41:43 +0200
From: "Ray Hunter (v6ops)" <>
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To: Juliusz Chroboczek <>
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Subject: Re: [homenet] Updating DNS [was: How many people have installed the homenet code?]
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> Juliusz Chroboczek <>
> 12 May 2016 15:10
> If I'm reading you correctly, Ray, you're promoting unstable naming.
Not promoting. Looking at the consequences.
>    If
> I have two routers called trurl and pirx in my network, then my printer
> will becalled diablo630.pirx.home whe pirx is up, diablo630.trurl.home
> when trurl is up, and either I reconfigure all of my hosts every time
> I swap a router, or rely on the DNS search list being correct?
>> We have multiple independent address spaces (ULA per router + GUA per
>> provider),
actually I was thinking more along the lines of the printer being called

diablo630.default_zone.ula1.home (ULA1)


diablo630.default_zone.ula2.home (ULA2 if it exists)

and (GUA1)

and (GUA2)


The DNSSL would indeed be updated automatically when the homenet 
autoconfigures, and advertised by RA.

The name registration and resolution for the various namespaces could 
run independently.
> No, we have a GUA per provider, and *optionally* a single ULA for the
> whole Homenet:
>        An HNCP router SHOULD create a ULA prefix if there is no other IPv6
>        prefix with a preferred time greater than 0 in the network.  It MAY
>        also do so if there are other delegated IPv6 prefixes, but none of
>        which is locally generated [...]  In case multiple locally generated
>        ULA prefixes are present, only the one published by the node with
>        the greatest node identifier is kept
Thanks for that explanation.
>> If a new router is added, a new ULA is added,
> No, that's not the case.
What happens if that new router has been booted stand-alone (so it 
creates its own ULA), and then joins the Homenet by being plugged in, 
and has a higher node identifier?

Shouldn't this be a voting mechanism to retain the "most popular" 
existing ULA?
>> If a router is removed or dies, the ULA prefix expires
> Nope.  If a router dies, any ULA should remain stable, even if it's the
> router who originally generated the ULA that dies:
>     When a new ULA prefix is created, the prefix is selected [...] using
>     the last non-deprecated ULA prefix
> That's the whole point of using a ULA.
Well even then you have the corner case of a split, stable operation, 
remerge, where one of the two ULA prefixes will disappear.

If the namespace relies in any way on the ULA, it'll change if the ULA 

If the namespace doesn't rely on the ULA, we'll likely get hit by the 
same (security) problems as mobile devices moving between disjoint 
.local networks.

Or else we have to manually configure a "Homenet root name"/ "Homenet