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

From: George Mitchell <[email-masked]>
Date: Tue, 10 Jul 2012 20:49:30 -0400

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

---

From: Mark Andrews <[email-masked]>
Date: Wed, 11 Jul 2012 11:35:29 +1000

In message <[email-masked]>, George Mitchell writes:
> --------------------------------------------------------------------
> IETF IPv6 working group mailing list
> [email-masked]
> 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.

-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: [email-masked]

---

From: George Mitchell <[email-masked]>
Date: Tue, 10 Jul 2012 22:05:16 -0400

> advertised mss from 1440. "route -n get -inet6 ::" will show you

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

---

From: Mark Andrews <[email-masked]>
Date: Wed, 11 Jul 2012 12:54:21 +1000

> 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

---

From: George Michaelson <[email-masked]>
Date: Wed, 11 Jul 2012 13:38:31 +1200

IETF should be running on a clamped MSS. The only benefits of floating MTU upwards is an efficiency gain which is almost irrelevant for a text-mainly website of this nature.

It would be lovely if they could rely on the other end, but a governance body should be reachable all the time.

-G

(in my HO, and a private opinion unrelated to my employer)

---

From: Glen <[email-masked]>
Date: Tue, 10 Jul 2012 19:40:07 -0700

On Tue, Jul 10, 2012 at 09:47:15PM -0400, George Mitchell wrote:
> We now return you to your normal working group traffic.     -- George

Thank you all!  I'm glad it's working.  

I'll be here if you need anything else - See you all in Vancouver!

Glen

---

From: Jeroen Massar <[email-masked]>
Date: Wed, 11 Jul 2012 11:13:35 +0200

On 2012-07-11 04:54, Mark Andrews wrote:
[..]
> to correctly sent PTB's you will then be in a position to report

I am fairly sure that NTT does generate and pass through PTBs, if the
user filters them incoming is a different question though.

The problem in this case seems to be the forgetting to configure an MTU
on an tunnel.

A better thing is to ask/check what the real MTU of the tunnel is.
Likely it is even up to 1480 depending on the underlying path.

Of course even better is to get rid of the tunnel and go native ;)

On 2012-07-11 03:38, George Michaelson wrote:
> IETF should be running on a clamped MSS. The only benefits of
> floating MTU upwards is an efficiency gain which is almost irrelevant
> for a text-mainly website of this nature.
>
> It would be lovely if they could rely on the other end, but a
> governance body should be reachable all the time.

No, the connectivity on the side of the user should be configured
properly. Adding hacks is not the way to go and does not solve the
general problem of misconfiguration that one can't hack around.

Greets,
 Jeroen

---

From: George Mitchell <[email-masked]>
Date: Tue, 10 Jul 2012 21:47:15 -0400

> advertised mss from 1440. "route -n get -inet6 ::" will show you

Thanks very much -- your diagnosis is correct!  Using
"route change -inet6 :: -mtu 1280" fixed the problem for www.ietf.org
and all the other sites I've been having problems with, too.

---

From: Simon Perreault <[email-masked]>
Date: Wed, 11 Jul 2012 08:43:47 -0400

> It would be lovely if they could rely on the other end, but a governance body should be reachable all the time.

Are you suggesting we stop eating our own delicious dog food?

Simon
-- 
DTN made easy, lean, and smart --> http://postellation.viagenie.ca
NAT64/DNS64 open-source        --> http://ecdysis.viagenie.ca
STUN/TURN server               --> http://numb.viagenie.ca

---

From: Thomas Dineen <[email-masked]>
Date: Wed, 11 Jul 2012 09:22:24 -0700

Why don't you just use IPv4 and stop bothering us????????

    We are busy to busy with the next boondoogle to worry about IPv6 
Bugs!!!!!!

Thomas Dineen