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

Lee Howard Lee at
Thu Jan 17 16:01:10 UTC 2013

On 1/17/13 9:54 AM, "William Herrin" <bill at> wrote:

>On Thu, Jan 17, 2013 at 5:06 AM, . <oscar.vives at> wrote:
>> The people on this list have a influence in how the Internet run, hope
>> somebody smart can figure how we can avoid going there, because there
>> is frustrating and unfun.
>"Free network-based firewall to be installed next month. OPT OUT HERE
>if you don't want it."

I haven't heard anyone talking about carrier-grade firewalls.  To make CGN
work a little, you have to enable full-cone NAT, which means as long as
you're connected to anything on IPv4, anyone can reach you (and for a
timeout period after that).  And most CGN wireline deployments will have
some kind of bulk port assignment, so the same ports always go to the same
users.  NAT != security, and if you try to make it, you will lose more
customers than I predicted.

>It's not a hard problem. There are yet plenty of IPv4 addresses to go
>around for all the people who actually care whether or not they're
>behind a NAT.

I doubt that very much, and look forward to your analysis supporting that


>Bill Herrin
>William D. Herrin ................ herrin at  bill at
>3005 Crane Dr. ...................... Web: <>
>Falls Church, VA 22042-3004

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