[153248] in North American Network Operators' Group
Re: IPv6 day and tunnels
daemon@ATHENA.MIT.EDU (bmanning@vacation.karoshi.com)
Sun Jun 3 23:28:23 2012
Date: Mon, 4 Jun 2012 03:26:20 +0000
From: bmanning@vacation.karoshi.com
To: Joe Maimon <jmaimon@ttec.com>
In-Reply-To: <4FCC17F4.3020105@ttec.com>
Cc: North American Networking and Offtopic Gripes List <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Sun, Jun 03, 2012 at 10:05:40PM -0400, Joe Maimon wrote:
>
>
> Joe Maimon wrote:
>
> >Looks like a tunnel mtu issue. I have not as of yet traced the
> >definitive culprit, who is (not) sending ICMP too big, who is (not)
> >receiving them, etc.
> >
>
> The culprit is the v6 tunnel, which wanders into v4 ipsec/gre tunnels,
> which means the best fix is ipv6 mtu 1280 on the tunnels, and possibly
> on the hosts. PMTUD works fine, just comes up with the wrong answer.
>
> 1280, the new 1500.
>
>
> >Joe
actually, to be safe, 1220.
/bill
