In message <9634AA8C-C8FD-4AFE-A888-82C9C326636D@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: marka@isc.org
-- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org