On Mon, 3 Mar 2025 14:24:15 +0100 Daniel =?utf-8?Q?Gr=C3=B6ber?= <d...@darkboxed.org> wrote: > Package: dhcpcd > Version: 1:9.4.1-24~deb12u4 > Severity: normal > X-Debbugs-Cc: d...@darkboxed.org > > Hi Martin, > > I was just looking through my dhcpcd.conf again and was reminded that I've > had to set `noipv4ll` very early on when starting to use dhcpcd and I've > had it ever since. Now that I think about it I also remember complaints > from collegues about this feature breaking their systems at very > inopportune times. > > I think we should disable IPv4LL for trixie. > > IPv6 link-locals perform the same function but with less breakage since > arguably more software is used to them being enabled. Since RFC 6540 "IPv6 > Support Required for All IP-Capable Nodes" is a thing I don't see any point > in having this legacy feature enabled by default. > > Ofc. I don't remember exactly what the problems with it were right now, but > I'll probably remember later if I think about it a while. IIRC it was > something to do with software incorrectly thinking the machine is online > due to the IPv4LL address/route, but I'm not sure.
I don't oppose disabling this – quite the contrary: I'd rather avoid dhcpcd falling back to IPv4LL if dhcpcd fails at getting a response from DHCPv4; I'd rather have it background its IPv4 process and retry DHCPv4 at regular intervals, just like dhclient does. However, I'm not entirely convinced that we can presume IPv6LL to be available at all times. I welcome opinions on this specific point. I also ponder whether we can claim to offer a suitable substitute for avahi-autoipd anymore if we disable IPv4LL in dhcpcd's stock configuration. Martin-Éric
