In message <9634aa8c-c8fd-4afe-a888-82c9c3266...@puck.nether.net>, Jared Mauch w rites: > If those interim hops are IPv4 only nodes part of 6/PE there could be a = > few things going on here. > > 1) Juniper u-RPF for family inet6 drops the mapped-v4-v6 source packets = > generated by a P/PE router > 2) FreeBSD (8.2 at least) doesn't seem to like mapped-v4-v6 source = > packets with its default traceroute (same for mtr on FreeBSD) > (tcpdump will show you the packets coming back, the freebsd traceroute6 = > seems to have a few unresolved bugs.. you need to force -w 1 as well = > likely)
I see nothing in tcpdump other than the outgoing traffic and the replies already noted. > 3) If end-to-end connectivity works,=20 > > Workarounds: > > the IPv4 only P/PE device should have some sort of IPv6 address placed = > on transit interfaces to allow TTL expired to be sourced from something = > capable (this IP doesn't need to be able to be reached/routed to that = > interface, just exist). > > I spent a lot of time looking at a similar problem and it ended up being = > a combination of #1 & #2 above. You will see this problem across The = > AT&T and Cogent networks in my experience. The path is going through AT&T. > - Jared > > On Jul 6, 2011, at 10:39 PM, Mark Andrews wrote: > > >=20 > > The below has been on going for over a week (yes it has been reported = > to HE) > > and the IETF). > >=20 > > Not returning time exceeded really make debugging routing problems = > hard. > >=20 > > Mark > >=20 > > traceroute6 -lI www.ietf.org > > traceroute6 to www.ietf.org (2001:1890:1112:1::1e) from = > 2001:470:1f00:ffff::5a1, 64 hops max, 16 byte packets > > 1 dviscorg.tunnel.tserv1.fmt.ipv6.he.net (2001:470:1f00:ffff::5a0) = > 172.669 ms 182.219 ms 170.424 ms > > 2 2001:470:0:1f::1 (2001:470:0:1f::1) 178.128 ms 171.926 ms = > 174.877 ms > > 3 gige-g4-8.core1.fmt2.he.net (2001:470:0:2d::2) 172.193 ms 171.265 = > ms 171.221 ms > > 4 10gigabitethernet6-4.core1.lax1.he.net (2001:470:0:18d::2) 198.338 = > ms 190.680 ms 182.413 ms > > 5 10gigabitethernet1-3.core1.lax2.he.net (2001:470:0:72::2) 178.924 = > ms 189.431 ms 180.538 ms > > 6 2001:470:0:1e6::2 (2001:470:0:1e6::2) 181.137 ms 179.374 ms = > 182.321 ms > > 7 * * * > > 8 * * * > > 9 * * * > > 10 * * * > > 11 * * * > > 12 2001:1890:1fff:ffff::1 (2001:1890:1fff:ffff::1) 262.713 ms * * > > 13 * * * > > 14 * * * > > 15 * * * > > 16 * * * > > 17 * * * > > 18 * * * > > 19 * * * > > 20 * * * > > 21 * * * > > 22 * * * > > 23 * * * > > 24 * * * > > 25 * * * > > 26 * * * > > 27 * * * > > 28 * * * > >=20 > > --=20 > > Mark Andrews, ISC > > 1 Seymour St., Dundas Valley, NSW 2117, Australia > > PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org > -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org
