google path mtu?

[Artem Viklenko]

On 19.01.2015 18:42, Brielle Bruns wrote:
> On 1/19/15 5:52 AM, Artem Viklenko wrote:
>> 19.01.2015 13:12, Mikael Abrahamsson написав(ла):
>>> On Mon, 19 Jan 2015, Ignatios Souvatzis wrote:
>>>
>>>> I had some problems at home, which is not tunneled, but a
>>>> less-than-1500-octet-mtu PPPoE DSL line, so - thinking it's tunnels
>>>> only ignores an increasing number of native private users.
>>>
>>> Well, PPPoE is a tunnel, but I guess that's splitting hairs.
>>>
>>> But regardless, I had trouble this morning with Youtube that might be
>>> related to the same issue.
>>>
>>
>>
>> One possible solution to force TCP MSS. For example on my FreeBSD
>> router at home i used PF's scrub rule for ipv6 tunnel to set
>> mss to 1220 bytes.
>>
>> If you use PPPoE as underlying technology, decrease this vale little
>> bit more - 1212 or less.
>>
>>
>>
> 
> Min MTU size allowable for ipv6 is 1280 according to RFC.  Wouldn't
> setting the MSS size to 1212 or 1220 essentially break that RFC as well
> (1220+40 < 1280) or does the RFC only explicitly state the MTU has to be
> at least 1280?
> 
> 

I'm not shure about RFC right now. But spending time trying to fugure
out why one or the other host can't be successfully reached using ipv6
finnally I stopped on this value. It may be not optimal, but it works
for me.

And indeed the main cause of this is the blocking ICPMv6 at the far end.


-- 
Sincerely yours,
 Artem Viklenko.