l.yimg.com (Yahoo!) over IPv6

[Jeroen Massar]

On 2013-08-19 23:10 , Phil Pennock wrote:
> On 2013-08-19 at 15:10 -0500, Frank Bulk wrote:
>> It works for me, too.
>>
>> Can you replicate this issue on other machines and vantage points?
> 
> I did, last week when I first saw it, to initially confirm it wasn't my
> home connection; at which point, I shrugged and left the issue.
> 
> At home, SixXS tunnel in USA, correctly configured.

While your end might be correctly configured, the path between you and
them might not be. Especially in the case of tunnels where a non-1500
byte MTU is likely to exist and silly admins still exist who think that
ICMP is evil and thus are stupid and drop it, especially that all
important ICMPv6-Packet-Too-Big packet.

> Replicated behaviour on my colo box in NL, which has native v6 in
> continuous operation for about seven years now.  AS8283.
>
> When I check now, the site has been fixed.  No idea if my questioning
> the status influenced that or not ...

Please note that the 'l' in l.yimg.com stands for load balancer, a
geographic one in this case.

See below, three different ASNs, three different results; and that is
just on the DNS/IP level, what actually happens at these sites is likely
another level of load-balancers with a bunch of machines behind it.
Stuff can be broken at any of those levels.

As such, a traceroute/tracepath is very useful when making any
statements like this, next to that all important wireshark dump which
will likely tell you where/why your TCP session hangs.

Greets,
 Jeroen

--

$ host l.yimg.com
l.yimg.com is an alias for fd-geoycs-l.gy1.b.yahoodns.net.
fd-geoycs-l.gy1.b.yahoodns.net is an alias for
ds-fo-anyycs-l.ay1.b.yahoodns.net.
ds-fo-anyycs-l.ay1.b.yahoodns.net has address 206.190.60.138
ds-fo-anyycs-l.ay1.b.yahoodns.net has address 206.190.60.139
ds-fo-anyycs-l.ay1.b.yahoodns.net has IPv6 address
2001:4998:f011:1fb::c:1101
ds-fo-anyycs-l.ay1.b.yahoodns.net has IPv6 address
2001:4998:f007:1fb::c:1103
ds-fo-anyycs-l.ay1.b.yahoodns.net has IPv6 address 2001:4998:8:1::2000
ds-fo-anyycs-l.ay1.b.yahoodns.net has IPv6 address
2001:4998:f007:1fb::c:1101
ds-fo-anyycs-l.ay1.b.yahoodns.net has IPv6 address 2001:4998:8:1::2001

$ host l.yimg.com
l.yimg.com is an alias for fd-geoycs-l.gy1.b.yahoodns.net.
fd-geoycs-l.gy1.b.yahoodns.net is an alias for
ds-fo-anyycs-l.ay1.b.yahoodns.net.
ds-fo-anyycs-l.ay1.b.yahoodns.net has address 66.196.65.174
ds-fo-anyycs-l.ay1.b.yahoodns.net has address 66.196.65.111
ds-fo-anyycs-l.ay1.b.yahoodns.net has address 66.196.65.112
ds-fo-anyycs-l.ay1.b.yahoodns.net has address 66.196.65.188
ds-fo-anyycs-l.ay1.b.yahoodns.net has IPv6 address
2a00:1288:f00e:1fc::c:1101
ds-fo-anyycs-l.ay1.b.yahoodns.net has IPv6 address
2a00:1288:f00e:1fc::c:1103

$ host l.yimg.com
l.yimg.com is an alias for fd-geoycs-l.gy1.b.yahoodns.net.
fd-geoycs-l.gy1.b.yahoodns.net is an alias for
ds-geoycs-l.gy1.b.yahoodns.net.
ds-geoycs-l.gy1.b.yahoodns.net is an alias for
ds-fo-vnycs-l.gy1.b.yahoodns.net.
ds-fo-vnycs-l.gy1.b.yahoodns.net is an alias for
ds-pxe-vnycs-p.gy1.b.yahoodns.net.
ds-pxe-vnycs-p.gy1.b.yahoodns.net has address 210.211.100.99
ds-pxe-vnycs-p.gy1.b.yahoodns.net has address 106.10.199.78
ds-pxe-vnycs-p.gy1.b.yahoodns.net has address 210.211.100.100
ds-pxe-vnycs-p.gy1.b.yahoodns.net has address 210.211.107.99
ds-pxe-vnycs-p.gy1.b.yahoodns.net has IPv6 address
2406:2000:f008:1fd::c:1101
ds-pxe-vnycs-p.gy1.b.yahoodns.net has IPv6 address 2406:2000:ac:5::c:1101
ds-pxe-vnycs-p.gy1.b.yahoodns.net has IPv6 address
2406:2000:f008:1fd::c:1103
ds-pxe-vnycs-p.gy1.b.yahoodns.net has IPv6 address 2406:2000:fc:402::c:2203