Re: Yes, I know this is the wrong mailing list

On 07/10/12 21:35, Mark Andrews wrote:
> In message <4FFCCD9A.10605@m5p.com>, George Mitchell writes:
>> So I was trying to browse the list of IETF mailing lists at www.ietf.org
>> to see who might be interested in my failures to browse sites like
>> yahoo.com and netflix.com following the onset of World IPv6 Day.
>>
>> Except that I can't browse www.ietf.org either.
>>
>> It did work previously.  I have a packet capture of the failing "telnet
>> www.ietf.org 80" session, if anyone is interested.  It looks fine and
>> proper, all the expected SYNs and ACKs as I sent my HTTP request,
>> except for the failure to return any HTTP response.  I'm running
>> FreeBSD 9.0-STABLE.  8.2-STABLE also fails the same way.  No doubt you
>> can reach www.m5p.com over IPv6; it's been working for years.
>>
>> Would one of you be able to tell me which mailing should I be using?
>> My apologies for the inappropriate message.         -- George Mitchell
>> --------------------------------------------------------------------
>> IETF IPv6 working group mailing list
>> ipv6@ietf.org
>> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
>> --------------------------------------------------------------------
>
> This sort of failure is usually a PMTUD failure.  If you are using
> a tunnel you need to ensure that your tunnel provider sends back
> PTB's.  The IETF servers do see the PTB's.  www.ietf.org does work
> over tunnels.
>
> You can test this theory by lowering the local mtu using "route
> change -inet6 :: -mtu 1280" (from memory).  This will change the
> advertised mss from 1440. "route -n get -inet6 ::" will show you
> the current values.
>

And so I don't have to do it repeatedly, I can change /etc/rc.conf from:
ipv6_defaultrouter="2001:418:3fd::fd"
to:
ipv6_defaultrouter="2001:418:3fd::fd -mtu 1280"

I appreciate all the help!                                     -- George