Problems with removing NAT from a network

Joel Jaeggli joelja at
Thu Jan 6 20:34:06 CST 2011

On 1/6/11 5:48 PM, Owen DeLong wrote:
> Doesn't all of this become moot if Skype just develops a dual-stack capable client
> and servers?

Really, only some fraction of the supernodes and the login servers need
to be dual stack.

> Owen
> On Jan 6, 2011, at 1:32 PM, Matthew Kaufman wrote:
>> On 1/6/2011 10:07 AM, Cameron Byrne wrote:
>>> Skype is not defined in an IETF RFC, so saying you need an RFC to move
>>> forward is bit confusing.
>> I don't see a disconnect at all. Skype also uses TCP and UDP, which are both subjects of RFCs.
>> That said, it doesn't need to be an RFC... just *a reliable way* of discovering the appropriate NAT64 prefix.
>>>  There are several methods that just work
>>> today,
>> Of the methods proposed in the survey draft, only one - the one that doesn't require the DNS64 spec or operator to make any changes (making an AAAA lookup for something you know only has an A record) - works but *only if* the mapping scheme is such that it is possible to successfully derive a functional prefix and the scheme from the results of that query.
>> So in other words, *if* the query results in an AAAA where, by inspection, you can guess where you'd need to stuff the IPv4 address bits *and* the resulting address causes the "right" NAT64 (if there's >1) to be used, then you're set.
>>> I am all for standards, but a closed platforms generally find ways to
>>> progress without or in spite of standards.  Skype is a closed
>>> platform.
>> No question. And for all you know we might be working on other ways around this problem, but none of them as elegant as a defined specification for how to discover the presence of a NAT64 and the mapping.
>>>> There's lots of other apps that don't work. Skype is just the squeaky wheel
>>>> because it is so popular.
>>> Please make a list and let us know.  Otherwise, this is just hand
>>> waving like the IPv4 literals sites.
>> I'll start with "peer to peer connectivity using RTMFP in Flash Player" and "BitTorrent". Both Flash Player and BitTorrent are fairly popular on desktop platforms.
>> I'm sure there's more.
>>> My advice to Skype is to come up with a solution to work for IPv6-only
>>> clients. That is my advice to all apps and all content.  IPv6-only
>>> clients are an obvious reality in an IPv4 exhausted world.
>> That's not the problem... the problem is reaching the existing base of IPv4 clients from those IPv6-only clients without making Skype relay all the traffic via servers somewhere, as I'm sure you know.
>>> You cannot seriously come to a network operators support mailing list
>>> and say that the network guys have to keep investing in network tweaks
>>> while you wait for a standards body to solve a problem for your closed
>>> non-standard applications.
>> I've been on this list since approximately the time it was formed, so I'm not coming here to ask for something. Just pointing out what will break.
>>> I also assure you, many mobile operators are pursuing this NAT64 path
>>> for the same reason I am.
>> Randy Bush would encourage his competitors to do just as you've done, I'm sure.
>> Matthew Kaufman

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