Test your connectivity for World IPv6 Day

Rémi Després remi.despres at free.fr
Mon Jun 6 22:17:11 CEST 2011

Le 6 juin 2011 à 21:38, Eric Vyncke (evyncke) a écrit :

> OTOH, if 'we' do not test IPv6 to 1500 bytes on Wednesday, then when could we try? Or do we really want to be stuck with 1280 byte for ever?
> Rémi, usually I am also advocating 1280 MTU on the server side, but, for W6D I would make an exception :-)

Fixing known problems of PMTU discovery before trying to do better than 1280 is an alternative that I recommend, especially for servers that have important contents to deliver.

Being unable to work with some servers even though path MTU's to them are well beyond 1280 is IMHO a pity, especially if the  solution is known and easy to implement.

In any case, that's a choice for each one to make.
I just express an opinion, with no personal stake. 
It is based on a preference that the W6D could show that IPv6 can now be safely used, with no need to turn it off after W6D. 


> -éric
>> -----Original Message-----
>> From: ipv6-ops-bounces+evyncke=cisco.com at lists.cluenet.de [mailto:ipv6-ops-
>> bounces+evyncke=cisco.com at lists.cluenet.de] On Behalf Of Rémi Després
>> Sent: lundi 6 juin 2011 17:59
>> To: owens at nysernet.org
>> Cc: ipv6-ops at lists.cluenet.de; Jared Mauch
>> Subject: Re: Test your connectivity for World IPv6 Day
>> Le 6 juin 2011 à 00:00, Bill Owens a écrit :
>>> On Fri, Jun 03, 2011 at 07:53:24AM -0400, Jared Mauch wrote:
>>>> On Thu, Jun 02, 2011 at 11:04:35AM +0200, Daniel Roesen wrote:
>>>>> On Wed, Jun 01, 2011 at 09:53:55AM -0700, Seth Mattinen wrote:
>>>>>> Both AfriNIC and ipv6.juniper.net are both working for me from work.
>>>>>> traceroute to ipv6.juniper.net (2620:103:c003::10), 30 hops max, 40 byte
>>>>>> packets
>>>>> The problem with ipv6.juniper.net is a PMTUD problem, not general
>>>>> reachability problem...
>> Unless there are good reasons to know that a longer PMTU applies to all their
>> connections, all servers SHOULD send IPv6 packets to off-link destinations
>> with 1280 octets as default PMTU.
>> Servers that don't do that are open for PMTU problems.
>> RD
>>>> 	I've not had luck reaching anyone there.  If someone from Juniper
>>>> is here please send me a note in private.
>>> Good luck with that. We discovered the PMTUD problem in February, told them
>> about it in March. . . and April. . . and it's still broken.
>>> Anyway, if you have a FreeBSD or OS X box with non-tunneled IPv6
>> connectivity, you can do the tests yourself:
>> http://www.wand.net.nz/scamper/pmtud
>>> Bill.

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