On Monday 17 June 2019 11:39:12 am Curt Howland wrote: > On Monday 17 June 2019, Gene Heskett <ghesk...@shentel.net> was heard > > to say: > > How is that resolved, by unroutable address blocks such > > as 192.168.xx.xx is now? > > Yes, IPv6 does have such allocations. The first 64bits is network > block, then the last 64bits are your local machine. > > fc00:: is the non-routed network. RFC1918 equiv. > > fe80:: is the link-local address which is not routed at all, it is > used solely between your device and the router. Personally, I would > have combined these two, but when IPv6 was being built they didn't > ask me.
Me neither, but then I've had it amply proved that my oar, in terms of steering this ship of state, isn't even the equ of a broken toothpick. Sigh... > Your device will always have an address built of its MAC address, with > FF FE in the middle of it, for every network block including link > local, like this: > > # ifconfig > enp1s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 > inet 192.168.85.86 netmask 255.255.255.0 broadcast > 192.168.85.255 > inet6 fe80::beae:c5ff:fe66:ec70 prefixlen 64 scopeid > 0x20<link> > inet6 2691:178d:8d80:efd:f92f:91cf:1240:640d prefixlen 64 > scopeid 0x0<global> > inet6 2691:178d:8d80:efd:beae:c5ff:fe66:ec70 prefixlen 64 > scopeid 0x0<global> > ether bc:ae:c5:66:ec:70 txqueuelen 1000 (Ethernet) > > These show the three entries which should always exist. The first is > the link-local address built from the MAC. Second, the allocated > network from my ISP, with a randomized local address for security > purposes. > > The third entry is the global network address and the local MAC based > address. Someone realized broadcasting your MAC address is not > particularly secure, so the randomized interface address has become > the norm. This third address is what you would put in your hosts > file. > > > how do the other machines on my local net, advertise their presence > > to the other machines on my local net. So I can still ssh -Y > > vna.coyote.den for instance, if I can ever make ssh work to a > > win-10-home edition box. > > You do so by either making a static fc00:: entry, or by knowing your > global network you can then just splice on the MAC local address > since the MAC local doesn't change. > > Unfortunately, because DHCP6 is really dynamic, and my ISP changes the > network blocks every once in a while, having the global network > entries and MAC local addresses in the hosts file has been a complete > waste of time. > I am lucky, my ISP uses the connecting MAC to translate to a fixed ipv4, that has not changed in 6 years. So my web page address in my sig has not changed in 6 years even if I swap the router as my standby unit has the good ones MAC cloned into it. So I get a registered STATIC domain for almost zip compared to the cost and monkey business associated with keeping a dynamic address uptodate globally. > Having fc00::MAC as a non-routed local RFC1918 default would have been > sooooo much easier, but no, IPv6 was not designed by network > engineers. It was designed by old AT&T phone engineers who were > pissed they were being put out of a job by competition, and wanted to > curse the world with increased complexity where none was needed. Chuckle, I subscribe to that theory myself. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene>
