I can fetch the header of websites via IPv6 but not the webpage, why?

[Ez Egy]

1452 is the good one :D


On Tue, Jan 21, 2014 at 9:30 PM, Ez Egy <ezegyemailcim123 at gmail.com> wrote:

> The solution was setting the MTU to 1480 in radvd in the router:
>
> option AdvLinkMTU       1480
> # option AdvLinkMTU     1452
>
>
> On Mon, Jan 20, 2014 at 5:22 PM, Ez Egy <ezegyemailcim123 at gmail.com>wrote:
>
>> As I said:
>>
>> 1) "I have a native IPv6 connection on my Desktop behind my router." ->
>> So there is no tunnel. Only native IPv6 that the Hungarian telekom.hugives.
>> 2) We will try out setting manually the MSS to 1392, hopefully that could
>> be a good workaround.
>> 3) We will try out the site: http://netalyzr.icsi.berkeley.edu/
>>
>> I will post the status here later, Thanks!
>>
>>
>>
>> On Mon, Jan 20, 2014 at 11:59 AM, Tore Anderson <tore at fud.no> wrote:
>>
>>> * Ez mail
>>>
>>> > Since I have no fr**king clue what could the problem be, I'm trying on
>>> > this list :)
>>>
>>> I concur 100% with Erik's assessment that this in all likelihood is a
>>> PMTUD problem, specifically in the web_server->your_desktop direction.
>>>
>>> I'd just like to add that the fact that you see it happening to several
>>> independent websites that are known to be operated by competent staff,
>>> and that the problem comes and goes, further indicates that it is due to
>>> rate-limiting of ICMPv6 PTB replies from your tunnel broker's tunneling
>>> router/server.
>>>
>>> The ICSI Netalyzr (http://netalyzr.icsi.berkeley.edu/) will give you
>>> very useful debugging output from the outside point of view. You might
>>> have to run it a few times to to reveal the MTU blackhole though, due to
>>> the problem's intermittent nature.
>>>
>>> As Erik mentions, lowering the TCP MSS will likely work around the
>>> problem. You can probably do this by having the RAs your router emits to
>>> the LAN advertise an MTU of 1452 to match your tunnel (which in turn
>>> should make your desktop default to a TCP MSS of 1392), and/or have your
>>> router rewrite ("clamp") the MSS value in TCP packets it forwards
>>> to/from the tunnel to 1392.
>>>
>>> Or, even better, get rid of the tunneling crap and get native IPv6. This
>>> is a very common problem for IPv6 tunnels. As a web site operator I
>>> would actually prefer it if people stayed IPv4-only until their ISP
>>> could provide them with properly supported IPv6 connectivity. Oh well...
>>>
>>> Tore
>>>
>>
>>
>
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