On Tue, Nov 21, 2023 at 12:35 AM Brian Inglis wrote: > > On 2023-11-20 17:45, Lee via Cygwin wrote: > > On Mon, Nov 20, 2023 at 7:13 PM Backwoods BC via Cygwin wrote: > >> > >> On Thu, Nov 16, 2023 at 12:41 PM Brian Inglis via Cygwin wrote: > >>> The whole IP v4 internet is available as a compatibility subnet > >>> ::ffff:0:a.b.c.d > >>> on IP v6, so there is no excuse for not supporting interconnection, as it > >>> will > >>> be required until the last backbone routers drop IP v4 support. > >> > >> Just a small correction for the mail archives as this appears solved. > >> The correct IPV6 address for the IPV4 address range is > >> ::ffff:a.b.c.d (no '0') > > > > If you're going for correcting the record, let's make it correct. > > ::ffff:a.b.c.d is not a solution for IPv6 => IPv4 interconnection over > > the Internet. > > > > from: https://www.rfc-editor.org/rfc/rfc5156 > > > > 2.2. IPv4-Mapped Addresses > > > > ::FFFF:0:0/96 are the IPv4-mapped addresses [RFC4291]. Addresses > > within this block should not appear on the public Internet. > > These internal addresses are used by dual stack hosts to allow clients or > servers to handle connections to IPv4 hosts the same as IPv6 hosts.
I think that at best you're terribly confused, but let's play this out. > Whereas ::ffff:0:0:0/96 == ::ffff:0:a.b.c.d allows IPv6 only hosts without > assigned IPv4 addresses to connect to IPv4 only hosts via SIIT see: > > https://www.rfc-editor.org/rfc/rfc7915 Stateless IP/ICMP Translation. I did see RFC 7915. I searched for 'ffff' and there were no matches. You need something else to back up your claim that ::ffff:0:0:0/96 == ::ffff:0:a.b.c.d allows IPv6 only hosts without assigned IPv4 addresses to connect to IPv4 only hosts. And please explain how an ipv6 host is going to get a packet with a 0::/8 address delivered across the internet. see: https://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xhtml An ipv6 prefix of 2000::/3 is defined as Global Unicast. In other words, an ipv6 unicast address MUST start off with 2000::/3 to be routed across the Internet. And look at footnotes 3 and 4 ::ffff:0:0/96 reserved for IPv4-mapped Address [RFC4291]. 0::/96 deprecated by [RFC4291]. Formerly defined as the "IPv4-compatible IPv6 address" prefix. Nothing about ::ffff:0:0:0/96 Regards, Lee -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple