Connectivity issue to/from 2001:500:61:28::70 (ISC) (Was: Strange IPv6 reachability problem)

[Jeroen Massar]

On 2011-06-20 01:08 , Seth Mattinen wrote:
> On 6/19/2011 3:59 PM, Jeroen Massar wrote:
> 
>> Nevertheless, the point stands, do you have a traceroute from
>> source->dest, as that might at least from that POV show where the path
>> is broken, a simple ping does not show that.
>>
> 
> traceroute to 2001:500:61:28::70 (2001:500:61:28::70), 30 hops max, 40
> byte packets
>  1  2607:fe70:1002::1  2.385 ms  2.341 ms  2.308 ms
>  2  2607:fe70:1001::1  10.189 ms  10.176 ms  10.178 ms
>  3  2607:fe70::14:1  10.536 ms  10.526 ms  11.711 ms
>  4  2607:fe70::5:2  14.571 ms  14.612 ms  14.616 ms
>  5  2607:fe70::a:1  11.650 ms  11.631 ms  11.618 ms
>  6  2607:fe70::4:1  11.582 ms  15.339 ms  16.466 ms
>  7  2600:6:300::6  20.470 ms * *
>  8  2600:0:2:1239:144:232:6:61  16.270 ms  16.079 ms  16.100 ms
>  9  2600:0:2:1239:144:232:9:224  16.996 ms 2600:0:2:1239:144:232:24:34
>  20.877 ms 2600:0:2:1239:144:232:9:224  20.790 ms
> 10  2600:0:2:1239:144:232:18:31  25.681 ms  25.753 ms  23.043 ms
> 11  2001:504:0:1::6939:1  23.044 ms  23.801 ms  20.814 ms
> 12  2001:470:0:32::2  29.885 ms  25.846 ms  25.799 ms
> 13  * * *

>From that it seems that the hop after that does not know how to send
packets back to you. From traceroutes from other vantage points we can
only assume that the next hop is ISC directly and that hop 12 does carry
a reverse containing pao1 which is close to ISC operations.

The inbound path from HE->Sprint seems to work though, thus this might
be a filtering issue somewhere in either network.

Peaking at GRH:

grh.sixxs.net> show bgp 2001:500:61:28::70
BGP routing table entry for 2001:500:61::/48
Paths: (107 available, best #72, table Default-IP-Routing-Table)

The destinatation lives in a /48 and if you look at the rest of that
output one can easily determine it has pretty good transit options
(1299/telia, 6939/he, 3257/Tiscali, 2914/NTT etc)
on the other hand though it is one of those special anycasted prefixes.

Best thing you can do is contact ISC (noc at isc.org works very quickly)
and various ISC folks are also present on the list.

I've fixed the subject for you so that those folks might easier reach
you. But instead of complaining on a public list you might want to just
mail the above mail addy directly which will cause your issue to be
resolved very quickly if they can do anything about it. You will want to
provide a lot more info that 'it is broken when I ping' though...

Greets,
 Jeroen