Slashdot: UK ISP PlusNet Testing Carrier-Grade NAT Instead of IPv6

Constantine A. Murenin mureninc at
Fri Jan 18 04:15:32 UTC 2013

On 17 January 2013 17:17, Owen DeLong <owen at> wrote:
> On Jan 17, 2013, at 4:30 PM, Jeff Kell <jeff-kell at> wrote:
>> On 1/17/2013 6:50 PM, Owen DeLong wrote:
>>> Vonage will, in most cases fail through CGN as will Skype, Xbox-360,
>>> and many of the other IM clients.
>> Not sure about Vonage, but Skype, Xbox, and just about everything else
>> imaginable (other than hosting a server) works just fine over NAT with
>> default-deny inbound here, and we have several thousand students in the
>> dorms that bang the heck out of those services.  Most applications have
>> adapted to the SOHO NATing router that is prevalent today on broadband
>> internet.  And if it didn't work, believe me, I'd hear about it :)
> NAT yes.
> NAT + NAT (NAT444 or CGN which is what we are talking about here), not so much.
> Owen

Once you are doing NAT and your immediate gateway does not supports
UPnP, what's the difference if it's NAT44 or NAT444?

I'm currently using NAT444444, with at least two layers of 802.11g
WiFi and 5 routers that seem to be doing independent NAT.  Two of them
are mine, then the other 3 are of the ISP, to whom I connect through
802.11g, and it generally works just fine; traceroute on the final
hosts shows 5 first hops being in various separate and networks.  iChat works.  SIP works, too (for both incoming
and outgoing voice call).  Even ssh connections stay alive for more
than 24h with a mere 240s keepalive setting.

IPv6 is obviously the solution, but I think CGN poses more
technological and legal problems for the carriers as opposed to their
clients or the general-purpose non-server non-p2p application

CGN breaks the internet, but it doesn't break non-p2p VoIP at all whatsoever.


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