[AusNOG] another ipv6 Q

[Jeroen Massar]

On 2014-07-03 02:36, Mark Newton wrote:
> 
> On Jul 3, 2014, at 2:30 PM, Jeroen Massar <jeroen at massar.ch> wrote:
> 
>> That is a single /32, out of the PA block of APNIC. Hence, unless
>> you convince every single ISP in the world to accept it, the only
>> thing you can announce is that /32, nothing else. More specifics
>> will properly be dropped.
> 
> Nope, complete bullshit.  I’m yet to find an ISP who isn’t
> comfortable with any announcement down to /56.  My /48 subnet is
> working just fine, thank you very much.

Which /48 is that? Is that out of a PA or a PI block? As the latter is
fine, the former will nicely be filtered in a LOT of locations.

As for /56s (and even /64) announcements, they only leak through
"transits" that want to up their prefix count... everybody else nicely
filters them out as they do not belong in BGP.

See below for proof in the pudding...

Greets,
 Jeroen

--

Lets take a small guess:

$ dig +short aaaa atdot.dotat.org
2001:44b8:60:4000:ffff::1
2406:c500:fffd:0:201:c0ff:fe0d:ced2
2001:44b8:60:4000:201:c0ff:fe0d:ced2

grh.sixxs.net> show bgp 2001:44b8:60:4000:ffff::1
BGP routing table entry for 2001:44b8::/32
Paths: (92 available, best #92, table Default-IP-Routing-Table)

grh.sixxs.net> show bgp 2406:c500:fffd:0:201:c0ff:fe0d:ced2
BGP routing table entry for 2406:c500:fffd::/48
Paths: (91 available, best #91, table Default-IP-Routing-Table)

grh.sixxs.net> show bgp 2001:44b8:60:4000:201:c0ff:fe0d:ced2
BGP routing table entry for 2001:44b8::/32
Paths: (92 available, best #92, table Default-IP-Routing-Table)

Seems that for those three networks, the /48 is already missed 1 peer...

Interesting that the last box has the same EUI-64, "multi-homed", hope
you got your source routing setup correctly.

$ traceroute6  2406:c500:fffd:0:201:c0ff:fe0d:ced2
 7  100ge1-1.core1.nyc4.he.net (2001:470:0:2cf::2)  98.264 ms  90.897 ms
 91.052 ms
 8  10ge10-3.core1.lax1.he.net (2001:470:0:10e::1)  152.487 ms  157.256
ms  152.498 ms
 9  * * *
10  2001:44b8:f010:2::2 (2001:44b8:f010:2::2)  400.680 ms
2001:4478:1:1::219 (2001:4478:1:1::219)  407.969 ms 2001:44b8:f010:2::2
(2001:44b8:f010:2::2)  401.448 ms
11  ae5.cr1.syd4.on.ii.net (2001:4478:1:1::2f)  408.296 ms  408.594 ms
408.043 ms
12  * * *
13  * * *
14  * * *
15  * * *

Nope, b0rked. Amazing that BGP made that one make it to Sydney.