SV: Why do we still need IPv4 when we are migrating to IPv6...

Thomas Schäfer thomas at
Fri Feb 13 11:35:46 CET 2015

Am 12.02.2015 um 19:59 schrieb Eric Vyncke (evyncke):
> Is it related to the paranoid option of blocking all inbound traffic? To
> mimick NAT44 ?

I afraid so.

Regarding to

"Even for users that do have native IPv6 – Teredo will be used to 
interact with IPv4-only peers, or in cases where IPv6 connectivity 
between peers is not functioning. In general, Xbox One will dynamically 
assess and use the best available connectivity method (Native IPv6, 
Teredo, and even IPv4). The implementation is similar in sprit to RFC 

and the practice in Germany to blocking all IPv6-inbound traffic the 
result is the problem for some gamers.

To find the guilty and the solution is sometimes complicated:

For instance Deutsche Telekom(DSL):

In general no IPv6-Traffic is blocked. But the soho-routers (speedport) 
  sold and leased by the Deutsche Telekom have a firewall, which can not 
be configured nor disabled. (only parts of IPv4 are configurable)
The customer has the choice to use router from a third party, e.g. avm.

In other cases he has no choice. (KD). But I am not sure about the exact 
situation because KD changes its strategies DS/DS-lite/IPv4-only and the 
statements by the customers are not unique.

(I am only a customer at DTAG and DFN)


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