Subject: RE: in-addr.arpa. in DHCPv6-PD scenario

From: Mikael Abrahamsson <[email-masked]>
Date: Sat, 1 Aug 2009 09:51:23 +0200 (CEST)

On Fri, 31 Jul 2009, Wes Beebee (wbeebee) wrote:

> Are you concerned about reverse-dns for items in the home or in the
> internet?

I would like for people in the homes to be able to set reverse-dns for 
their prefix, handle dynamic DNS updates etc. This could be done by the 
home CPE router, it could also be done elsewhere. The natural point would 
be the home CPE router somehow being involved since it's involved in the 
DHCPv6-PD process.

> For the home, I would imagine that if the IPv6 CPE router supported a
> local DNS server, then that server would also handle PTR queries.

Absolutely, but then again, I've had bad experiences with the quality of 
DNS recursive resolver software in home CPE routers, so perhaps we should 
try to come up with a more generic approach?

Would a "well known address" in the PD delegated prefix work here? 
PREFIX::53 for instance. This would of course have the problem that if the 
home CPE didn't support this (didn't allocate this address to itself) then 
you get in-addr lookup timesouts when hosts on the Internet tries to do 
this.

Should perhaps the DHCPv6-PD request from the client include an option 
where the client can ask for reverse DNS delegation of the space being PD 
requested, if it actually supports this? Then a WKA could be used, or the 
actual IPv6 address of the server wanting to be used could be provided to 
the DHCPv6 server and the ISP would then have to provide hook into the DNS 
server to set this CPE router provided IPv6 address (it would also have to 
be able to set an absolute address and a relative address I guess, since 
it at the time of the request does not know what prefix it's getting, or 
perhaps it should be done by a separate PD request after the PD-prefix is 
already known to the CPE router).

I tride to find a mention of how to provide a in-addr.arpa.-server 
involved in the DHCPv6-PD process but could find none, does this mean that 
there needs to be an addition to DHCPv6-PD to enable this behaviour?

Do people think it's a good idea? I personally like reverse-DNS 
historically, but when IPv6 hosts can take and leave IPs via SLAAC all the 
time, does it even make sense to have reverse-DNS? I still think it does.

-- 
Mikael Abrahamsson    email: [email-masked]

---

From: "Wes Beebee (wbeebee)" <[email-masked]>
Date: Mon, 3 Aug 2009 09:30:03 -0400

> Do people think it's a good idea? I personally like reverse-DNS
historically, but when IPv6 hosts can take and
> leave IPs via SLAAC all the time, does it even make sense to have
reverse-DNS? I still think it does.

For DHCPv6 clients in the home, you could have the DHCPv6 server in the
CPE Router also populate the reverse-DNS tree.  For SLAAC clients in the
home (the more usual case), you could snoop the NS(DAD) and consult a
MAC table of allowed clients and names and then populate the reverse DNS
tree.

The question for the working group is, is this behavior worthwhile to
standardize or should we just expect that vendors will do something
reasonable here?

- Wes

---

From: "Eric Vyncke (evyncke)" <[email-masked]>
Date: Mon, 3 Aug 2009 16:41:06 +0200

> I would like for people in the homes to be able to set 
> reverse-dns for their prefix, handle dynamic DNS updates etc. 
> This could be done by the home CPE router, it could also be 
> done elsewhere. The natural point would be the home CPE 
> router somehow being involved since it's involved in the 
> DHCPv6-PD process.

A complication is that some ISP (at least in Europe) want to change the delegated prefix every day (like they change now the IPv4 address every day). This would then also mean to clean/purge DNS information...

...%<.....%<..........

> 
> Do people think it's a good idea? I personally like 
> reverse-DNS historically, but when IPv6 hosts can take and 
> leave IPs via SLAAC all the time, does it even make sense to 
> have reverse-DNS? I still think it does.

Same feeling here

-éric

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From: Joe Abley <[email-masked]>
Date: Mon, 3 Aug 2009 11:44:37 -0400

On 3-Aug-2009, at 10:41, Eric Vyncke (evyncke) wrote:

> A complication is that some ISP (at least in Europe) want to change  
> the delegated prefix every day (like they change now the IPv4  
> address every day).

Why?

---

From: "Gunter Van de Velde (gvandeve)" <[email-masked]>
Date: Mon, 3 Aug 2009 17:51:52 +0200

Services differentiation.
They ask more money for a fixed address and they want to reuse that
business model

G/

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Joe Abley
Sent: maandag 3 augustus 2009 17:45
To: Eric Vyncke (evyncke)
Cc: Mikael Abrahamsson; Wes Beebee (wbeebee); [email-masked]
Subject: Re: in-addr.arpa. in DHCPv6-PD scenario

Why?

---

From: Joe Abley <[email-masked]>
Date: Mon, 3 Aug 2009 11:56:11 -0400

> They ask more money for a fixed address and they want to reuse that

I think they should be prepared to find out that it's cheaper and  
easier for them to change their business model.