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

In message <4FFCDF5C.80809@m5p.com>, George Mitchell writes:
> 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

You really should talk to your tunnel provider and get this fixed as
this only helps TCP connections.  It does not help UDP based
protocols.  Once your tunnel provider has fixed the tunnel ingress
to correctly sent PTB's you will then be in a position to report
broken web sites.

Mark
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka@isc.org