Date: Sat, 4 Oct 2025 12:46:58 -0400 From: Chris Ross <cross+freebsd@distal.com> To: freebsd-net@freebsd.org Subject: IPv6 routing, Verizon FiOS, dhcpcd Message-ID: <9A0A976D-EB8A-4ABF-B216-3CB6358C2559@distal.com>
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Good day. This is picking up after a long thread a couple weeks back: Subject: IPv6 networking problems in 14.3 Archive: = https://lists.freebsd.org/archives/freebsd-net/2025-September/007532.html So following Tom Pusateri=E2=80=99s suggestion, I pulled an old server = out of the rack, and set it up near the center of the house. =46rom here, I could disconnect everything and plug directly into the ethernet out to the = Verizon ONT. I=E2=80=99m running with a simplified rc.conf, and mostly the same = dhcpcd.conf as my real router. I am not using pf at all, nor most of the other = services the router uses. Just system DHCP from Verizon = 'ifconfig_bce1=3D=E2=80=9CSYNCDHCP=E2=80=9D' and dhcpcd. (Well, +ssh, +zfs, +ntpd, but=E2=80=A6) Lots and lots of testing showed me: 1. 14.1 and 14.3 seem to act the same 2. If dhcpcd starts up before the interface has a link, which it = frequently does, the Verizon LL router address is never reachable. 3. If I delay starting dhcpcd until after IPv4 connectivity is = established, dhcpcd sets up the same way, but the router LL is reachable, and IPv6 routing works. There are a couple issues here that complicate things. First, I=E2=80=99m= using dhcpcd for IPv6 only, which means delaying startup is fine. But, if someone were using it for general networking, that=E2=80=99s clearly a = blocker. Second, I cannot imagine why starting dhcpcd earlier caused the kernel to somehow become unable to reach the ISP v6 LL address for the router. If dhcpcd can=E2=80=99t talk to anything, it backs of and tries later. = When it tries later, it gets DHCP6 responses, and does what it should do.=20 However, the LL address that it gets from the RA just isn=E2=80=99t = reachable. =E2=80=9Cndp -an=E2=80=9D shows it as =E2=80=9C(incomplete)=E2=80=9D for = a second, then not at all. So, first, why if dhcpcd starts early does the system get into a state where it is unable to reach the advertised IPv6 router? And that this won=E2=80=99t ever fix itself. (2+ hours tested on test box, days/weeks = seen on original router) - Chris=
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