google path mtu?

[Lorenzo Colitti]

No, the minimum MTU is a requirement on links, not hosts. Hosts are always
allowed to send smaller packets than the MTU if they want to. Also, the MSS
includes TCP options, so it might be 1208 on a 1280-byte link.

On Tue, Jan 20, 2015 at 1:42 AM, Brielle Bruns <bruns at 2mbit.com> 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?
>
>
> --
> Brielle Bruns
> The Summit Open Source Development Group
> http://www.sosdg.org    /     http://www.ahbl.org
>
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