nanog mailing list archives
Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast
From: John Gilmore <gnu () toad com>
Date: Fri, 19 Nov 2021 12:14:00 -0800
Nick Hilliard wrote:
consider three hosts on a broadcast domain: A, B and C. A uses the lowest address, B accepts a lowest address, but C does not. Then A can talk to B, B can talk to C, but C cannot talk to A. This does not seem to be addressed in the draft.
Section 3.4. Compatibility and Interoperability. Many deployed systems follow older Internet standards in not allowing the lowest address in a network to be assigned or used as a source or destination address. Assigning this address to a host may thus make it inaccessible by some devices on its local network segment. [there's more...] If you think that section needs improving, please send suggested text. We're happy to explain the implications better. Joe Maimon <jmaimon () jmaimon com> wrote:
its a local support issue only.
That's also true. The only issues arise between your devices, on your LAN. Everybody else on the Internet is unaffected and can reach all your devices, including the lowest if your LAN uses it. Nothing forces you to use your lowest address, and we recommend that DHCP servers be configured by default to not to hand them out (no change from how they historically have been configured). We submitted a 6-line patch to the Busybox DHCP implementation in February to avoid hardcoded prevention of issuing a .0 or .255 address (which was wrong anyway, even without our proposal). The default in the config file continues to use a range excluding .0. The patch was merged upstream without trouble. See: https://github.com/schoen/unicast-extensions/blob/master/merged-patches/busybox/0001-Don-t-hardcode-refusing-to-issue-.0-or-.255-addresse.patch John
Current thread:
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast, (continued)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Mark Andrews (Nov 20)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Jay Hennigan (Nov 20)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Joe Maimon (Nov 20)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast J. Hellenthal via NANOG (Nov 21)
- FreeBSD users of 127/8 John Gilmore (Nov 22)
- Re: FreeBSD users of 127/8 Måns Nilsson (Nov 22)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Michael Thomas (Nov 21)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast bzs (Nov 21)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Joe Maimon (Nov 19)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Dave Taht (Nov 19)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast John Gilmore (Nov 19)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Jared Mauch (Nov 19)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Randy Bush (Nov 19)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Michael Thomas (Nov 19)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Jared Mauch (Nov 25)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Dave Taht (Nov 25)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Joe Maimon (Nov 18)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast bzs (Nov 18)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast John Curran (Nov 19)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast William Herrin (Nov 19)
- Re: Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast Owen DeLong via NANOG (Nov 20)