Re: [gentoo-desktop] python.org and ipv6

[Tom Fifield]

My apologies for not reading your post carefully.

I see an MTU of 1280 to www.python.org at my end - ipv6 tun device on my 
router is set to this, so I think it can deal with the 1500 MTU on my 
local machine's interface. Nice spotting :)


Regards,

Tom

gummay ~ # tracepath6 www.python.org
  1?: [LOCALHOST]                      pmtu 1500
  1:  2001:44b8:62:120::1                        0.695ms
  1:  2001:44b8:62:120::1                        0.630ms
  2:  2001:44b8:62:120::1                        0.691ms pmtu 1280
*snip*
24:  dinsdale.python.org                      460.627ms reached
      Resume: pmtu 1280 hops 24 back 51




Lindsay Haisley wrote:
> On Sat, 2009-05-16 at 13:07 +1000, Tom Fifield wrote:
>> I have encountered this problem before, however www.python.org works
>> fine on ipv6 for me. Many cases where things fail is because DNS
>> resolves the AAAA record, but the ISP/upstream providers don't have IPv6
>> connectivity to the site.
>
> I'm using a v6->v4 tunnel broker so my ISP is out the loop, what's more,
> as I said,
>
>> www.python.org also
>> resolves with an aaaa record (2001:888:2000:d::a2), and I can ping6
>> the server, so I know that routing is OK.
>
> It looks as if the problem may be related to MTUs.  I did a bit of
> jiggery-pokery with MTUs, setting the MTU for the IF on my desktop
> system slightly lower than the MTU on the LAN IF of my router, and it
> appears that the problem is solved for now, at least.
>
> I've seen network problems before with MTU issues, especially where UDP
> packets are involved, as they may be with the tunnel broker.
>