From nobody Mon Oct 6 04:34:52 2025 X-Original-To: freebsd-net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4cg5zM3ppyz69d7C for ; Mon, 06 Oct 2025 04:35:11 +0000 (UTC) (envelope-from pusateri@keehole.org) Received: from kem.keehole.org (kem.keehole.org [136.41.224.255]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4cg5zK5pClz48MF for ; Mon, 06 Oct 2025 04:35:09 +0000 (UTC) (envelope-from pusateri@keehole.org) Authentication-Results: mx1.freebsd.org; dkim=pass header.d=keehole.org header.s=202408 header.b=A8VLqAxE; dmarc=pass (policy=none) header.from=keehole.org; spf=pass (mx1.freebsd.org: domain of pusateri@keehole.org designates 136.41.224.255 as permitted sender) smtp.mailfrom=pusateri@keehole.org Received: from smtpclient.apple (unknown [136.41.224.198]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by kem.keehole.org (Postfix) with ESMTPSA id F2D9D77F91; Mon, 06 Oct 2025 00:35:02 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=keehole.org; s=202408; t=1759725303; bh=85hdl3iEHC/7OCQuyPF1ItVKGETy7/z5T2WIZWQDRYM=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From; b=A8VLqAxELZlxXBXIDrGEUyAptAXKZ2jbavM0Wg4IG2SzpgGmSlMRg+eIytbLLe/UN NxRZyf7oiQ8BJiC0jIScZ4UfX//7Wb0pFztvYzgyU2OpMA+c5H4oG7vsftBt2ak/+W Dhp5a5tX8SnG2GKyPyc5wgDtiKYYtI29pQIN8TQ8bcTYhGS/Cl74tMlz+FmZo/Br35 cvksfEzCn5H5zvCG7HPmvQ85mBJ5R6L8Lg7rRjvUqwfoUq9hkhV7PVxN75PjjL9cBg tsjjWXdoOCmm2JkIGv+fIfrPCTrHx428DTxqP1Mcmg8wRxL5wdkP6QSXzBrSs7lKkI /hpC2ATTp6Rrg== Content-Type: text/plain; charset=utf-8 List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@FreeBSD.org Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3826.700.81\)) Subject: Re: IPv6 routing, Verizon FiOS, dhcpcd From: Tom Pusateri In-Reply-To: <9A0A976D-EB8A-4ABF-B216-3CB6358C2559@distal.com> Date: Mon, 6 Oct 2025 00:34:52 -0400 Cc: freebsd-net@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <9A0A976D-EB8A-4ABF-B216-3CB6358C2559@distal.com> To: Chris Ross X-Mailer: Apple Mail (2.3826.700.81) X-Spamd-Bar: --- X-Spamd-Result: default: False [-3.71 / 15.00]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-0.97)[-0.972]; NEURAL_HAM_SHORT(-0.93)[-0.934]; DMARC_POLICY_ALLOW(-0.50)[keehole.org,none]; R_SPF_ALLOW(-0.20)[+mx]; R_DKIM_ALLOW(-0.20)[keehole.org:s=202408]; ONCE_RECEIVED(0.20)[]; MIME_GOOD(-0.10)[text/plain]; DKIM_TRACE(0.00)[keehole.org:+]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; ARC_NA(0.00)[]; RCVD_COUNT_ONE(0.00)[1]; RCVD_VIA_SMTP_AUTH(0.00)[]; MIME_TRACE(0.00)[0:+]; TO_MATCH_ENVRCPT_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; ASN(0.00)[asn:16591, ipnet:136.32.0.0/11, country:US]; MLMMJ_DEST(0.00)[freebsd-net@freebsd.org]; APPLE_MAILER_COMMON(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; TAGGED_RCPT(0.00)[freebsd]; TO_DN_SOME(0.00)[] X-Rspamd-Queue-Id: 4cg5zK5pClz48MF Getting a router advertisement is independent of getting an IA_NA global = address for your upstream interface, however, the provider could be = filtering your router until it gets a DHCPv6 round trip.=20 Use tcpdump to capture the router advertisements on your upstream = interface. This will show router advertisements and router = solicitations. In my case, they=E2=80=99re sent about every 24 minutes. = A router solicitation would trigger one at restart. # tcpdump -i igc0 -v 'icmp6 and (ip6[40] =3D=3D 134 or ip6[40] =3D=3D = 133)' tcpdump: listening on igc0, link-type EN10MB (Ethernet), snapshot length = 262144 bytes 23:28:22.673448 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) = payload length: 24) fe80::1 > fe80::7e10:c9ff:fe3d:fb2c: [icmp6 sum ok] = ICMP6, router advertisement, length 24 hop limit 64, Flags [managed, other stateful], pref medium, router = lifetime 4500s, reachable time 0ms, retrans timer 180000ms source link-address option (1), length 8 (1): 00:00:5e:00:01:b7 23:52:34.673680 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) = payload length: 24) fe80::1 > fe80::7e10:c9ff:fe3d:fb2c: [icmp6 sum ok] = ICMP6, router advertisement, length 24 hop limit 64, Flags [managed, other stateful], pref medium, router = lifetime 4500s, reachable time 0ms, retrans timer 180000ms source link-address option (1), length 8 (1): 00:00:5e:00:01:b7 00:14:01.673272 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) = payload length: 24) fe80::1 > fe80::7e10:c9ff:fe3d:fb2c: [icmp6 sum ok] = ICMP6, router advertisement, length 24 hop limit 64, Flags [managed, other stateful], pref medium, router = lifetime 4500s, reachable time 0ms, retrans timer 180000ms source link-address option (1), length 8 (1): 00:00:5e:00:01:b7 See if you have a default route and try pinging the default IPv6 route: # netstat -6nra|grep default default fe80::1%igc0 UG = igc0 # ping6 fe80::1%igc0 PING(56=3D40+8+8 bytes) fe80::7e10:c9ff:fe3d:fb2c%igc0 --> fe80::1%igc0 16 bytes from fe80::1%igc0, icmp_seq=3D0 hlim=3D255 time=3D1.190 ms 16 bytes from fe80::1%igc0, icmp_seq=3D1 hlim=3D255 time=3D2.644 ms ^C If no ping, see if you have a Mac address for the router: # ndp -a | grep fe80::1%igc0 fe80::1%igc0 00:00:5e:00:01:b7 igc0 15s = R R Does this act the same with another DHCPv6 client like KAME dhcp6c = instead of using dhcpcd? Tom > On Oct 4, 2025, at 12:46=E2=80=AFPM, Chris Ross = wrote: >=20 > Good day. This is picking up after a long thread a couple weeks back: >=20 > Subject: IPv6 networking problems in 14.3 > Archive: = https://lists.freebsd.org/archives/freebsd-net/2025-September/007532.html >=20 > 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) >=20 > Lots and lots of testing showed me: >=20 > 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. >=20 > There are a couple issues here that complicate things. First, I=E2=80=99= m 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. >=20 > 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) >=20 > - Chris >=20