On Wed, Jan 10, 2024 at 11:06 AM Tom Beecher <beec...@beecher.cc> wrote: >> >> There's a whole bunch of software out there that makes certain >> assumptions about allowable ranges. That is, they've been compiled with >> a header that defines .. > > > Of course correct. It really depends on the vendor / software / versions in > an environment. A lot of vendors removed that years ago, because frankly a > lot of large networks have been using 240/4 as pseudo RFC1918 for years. > Others have worked with smaller vendors and open source projects to do the > same. > > It's consistently a topic in the debates about 240/4 reclassification.
There's debates still? I gave up. After making 240/4 and 0/8 work across all of linux and BSD and all the daemons besides bird (which refused the patch , I took so much flack that I decided I would just work on other things. So much of that flack was BS - like if you kill the checks in the OS the world will end - that didn't happen. Linux has had these two address ranges just work for over 5 years now. 240/4 is intensely routable and actually used in routers along hops inside multiple networks today, but less so as a destination. I would really like, one day, to see it move from reserved to unicast status, officially. I would have loved it if 0/8 was used by a space RIR, behind CGNAT, for starters, but with a plan towards making it routable. I am not holding my breath. The principal accomplishment of the whole unicast extensions project was to save a nanosecond across all the servers in the world on every packet by killing the useless 0/8 check. That patch paid for itself the first weekend after that linux kernel deployed. It is the simplest, most elegant, and most controversial patch I have ever written. https://news.ycombinator.com/item?id=20430096 > > On Wed, Jan 10, 2024 at 10:45 AM Michael Butler <i...@protected-networks.net> > wrote: >> >> On 1/10/24 10:12, Tom Beecher wrote: >> > Karim- >> > >> > Please be cautious about this advice, and understand the full context. >> > >> > 240/4 is still classified as RESERVED space. While you would certainly >> > be able to use it on internal networks if your equipment supports it, >> > you cannot use it as publicly routable space. There have been many >> > proposals over the years to reclassify 240/4, but that has not happened, >> > and is unlikely to at any point in the foreseeable future. >> >> While you may be able to get packets from point A to B in a private >> setting, using them might also be .. a challenge. >> >> There's a whole bunch of software out there that makes certain >> assumptions about allowable ranges. That is, they've been compiled with >> a header that defines .. >> >> #define IN_BADCLASS(i) (((in_addr_t)(i) & 0xf0000000) == 0xf0000000) >> >> Michael >> -- 40 years of net history, a couple songs: https://www.youtube.com/watch?v=D9RGX6QFm5E Dave Täht CSO, LibreQos
