This will break a significant number of existing deployments where people have come to depend on a feature in Linux where any address within 127.0.0.0/8 can be “listened” and operate as a valid loopback address without configuring the addresses individually as unicast on the interface.
In fact, this is true of any prefix assigned to the loopback interface, but 127.0.0.0/8 is automatic and difficult to change. While I’m not sure this implementation in the Linux kernel was such a wonderful idea, it is widely deployed and in use in a number of environments. If we’re still using IPv4 widely enough that GUA space matters, we will have far bigger problems than the lack of available GUA for it. Owen > On Nov 17, 2021, at 16:15 , William Herrin <b...@herrin.us> wrote: > > On Wed, Nov 17, 2021 at 3:31 PM Jay R. Ashworth <j...@baylink.com> wrote: >> This seems like a really bad idea to me; am I really the only one who >> noticed? >> >> https://www.ietf.org/id/draft-schoen-intarea-unicast-127-00.html > > Hi Jay, > > I think it's a good idea. It won't be usable any time in the next two > decades but if we're still using IPv4 in two decades we'll be glad to > have anything we can scrounge. Why not ask OS authors to start > assigning 127.0.0.1/16 to loopback instead of 127.0.0.1/8? > > Regards, > Bill Herrin > > > -- > William Herrin > b...@herrin.us > https://bill.herrin.us/
