Re: [BEHAVE] [3gv6] DNS64 Resolvers and Dual-Stack Hosts, draft-wing-behave-dns64-config-00

Dan Wing escribió:
>  
>
>   
>> -----Original Message-----
>> From: marcelo bagnulo braun [mailto:marcelo@it.uc3m.es] 
>> Sent: Friday, January 08, 2010 3:15 AM
>> To: Behcet Sarikaya
>> Cc: Dan Wing; 3gv6@ietf.org; Behave WG
>> Subject: Re: [BEHAVE] [3gv6] DNS64 Resolvers and Dual-Stack 
>> Hosts, draft-wing-behave-dns64-config-00
>>
>> Behcet Sarikaya escribió:
>>     
>>> Hi Dan,
>>>   I read your draft. 
>>> Looking from mobility point of view, I think that on page 
>>>       
>> 4, to the protocols that have trouble with NAT64, MIPv6 
>> should be added. 
>>     
>>>   
>>>       
>> I don't think the problem is specific to MIPv6. the problem 
>> is general 
>> to any configuration that:
>> - Does not use the Well know prefix (i.e. if the WK prefix is used, 
>> there is no problem and everything works just fine)
>> - The node is using a dns server that is not in the same 
>> domain that the 
>> NAT64 the node is connected too.
>>     
>
> But well-known prefix does not 'just work' if the local network
> is not operating a NAT64 at all.  For example, if the local
> network is dual-stack, it has no reason to operate a NAT64.
>   
are you assuming that the mobile node is dual stack of IPv6 only?

Regards, marcelo


> But if the dual-stack host is pointing to an off-site DNS64, 
> and that off-site DNS64 is returning synthesized AAAA records
> containing the well-known prefix, the dual-stack host will
> be unable to connect to anything without timing out and
> falling back to IPv4.
>
>   
>> For example you could have the same problem if you are 
>> connected to the local network that is providing NAT64 
>> services and you decide to use a DNS server that is 
>> located in a different domain.
>>     
>
> Yes, we should encourage hosts to Not Do That with DNS64.
>
>
> I just read draft-haddad-mext-nat64-mobility-harmful-00, and I believe the
> problems described in its Section 3 could be resolved by the MN following the
> recommendation of draft-savolainen-mif-dns-server-selection -- namely, only
> use a DNS response on the same interface as the DNS response itself.  This
> means that the DNS query should be sent over the same interface as the tunnel
> interface (to the foreign network), and the response is only valid for that
> same interface.  This can be difficult on many stacks, though (because many
> stacks do not concern themselves with which interface received a DNS
> response).  That difficulty can be eased if all the networks are using NAT64
> with their own network-specific prefix (NSP, as described in
> draft-ietf-behave-address-format), as the different NSP allows RFC3484 address
> selection rules can choose the correct interface.
>
> -d
>
>
>   
>> Regards, marcelo
>>
>>     
>>> However the solutions you proposed would not be good for 
>>>       
>> MIPv6. That's the problem I have with your draft. I have not 
>> followed related discussions on Behave list, maybe some 
>> solutions have already been proposed there.
>>     
>>> Regards,
>>>
>>> Behcet
>>>
>>>
>>>
>>> ----- Original Message ----
>>>   
>>>       
>>>> From: Dan Wing <dwing@cisco.com>
>>>> To: 3gv6@ietf.org; Behave WG <behave@ietf.org>
>>>> Sent: Thu, January 7, 2010 4:26:46 PM
>>>> Subject: [3gv6] DNS64 Resolvers and Dual-Stack Hosts, 
>>>>         
>> draft-wing-behave-dns64-config-00
>>     
>>>> draft-wing-behave-dns64-config-00 should be of interest to 
>>>>         
>> both 3Gv6 and
>>     
>>>> BEHAVE.  The draft is related to recent threads on both 
>>>>         
>> mailing lists
>>     
>>>> discussing a DNS64 recursive resolver being used by a 
>>>>         
>> dual-stack host.
>>     
>>>> Abstract:
>>>>   Some networks are expected to support IPv4-only, dual-stack, and
>>>>   IPv6-only hosts at the same time.  Such networks also 
>>>>         
>> want to IPv6/
>>     
>>>>   IPv4 translation for the IPv6-only host so it can access 
>>>>         
>> servers on
>>     
>>>>   the IPv4 Internet.  On such a network, the synthesized 
>>>>         
>> AAAA responses
>>     
>>>>   from a DNS64 can cause traffic to be translated.  This document
>>>>   describes two solutions to avoid that translation:  
>>>>         
>> modifying default
>>     
>>>>   address selection on the host, and using DHCP to 
>>>>         
>> configure different
>>     
>>>>   DNS recursive resolvers.
>>>>
>>>> http://tools.ietf.org/html/draft-wing-behave-dns64-config-00
>>>>
>>>> Comments welcome.
>>>>
>>>> -d
>>>>
>>>> _______________________________________________
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>>>> 3gv6@ietf.org
>>>> https://www.ietf.org/mailman/listinfo/3gv6
>>>>     
>>>>         
>>>
>>>       
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>>>
>>>   
>>>       
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