I can't imagine any case in where the ability to arbitrarily punch through your firewall (as an attacker) once I have any kind of foothold is a good feature. It's explicitly one reason why I highly dislike 1:many NAT, having been party to cleanup of attacks where such technique was leveraged. -----Original Message----- From: William Herrin via NANOG <nanog@lists.nanog.org> Sent: Thursday, June 18, 2026 5:06 AM To: North American Network Operators Group <nanog@lists.nanog.org> Cc: William Herrin <bill@herrin.us> Subject: Re: IPv4 flag day On Wed, Jun 17, 2026 at 10:39 AM Douglas Fischer via NANOG <nanog@lists.nanog.org> wrote:
NAT is cancer! NAT in IPv6 is spreading cancer cells to all the organs of a new, healthy body.
Hi Douglas, Hate on it all you want, 1:many NAT renders my internal network not just inaccessible from the Internet but inaddressible as well. That's a feature not a bug. It's a feature I want for some of my subnets. When I get around to deploying IPv6 on those subnets it's a feature I will use. You don't have to like it. It's not your network. Regards, Bill Herrin -- For hire. https://bill.herrin.us/resume/ _______________________________________________ NANOG mailing list https://lists.nanog.org/archives/list/nanog@lists.nanog.org/message/VXIEFJOV...