Toward more sensible whitelisting

Brian E Carpenter brian.e.carpenter at
Wed Jun 15 23:46:07 CEST 2011

On 2011-06-16 03:51, Tony Finch wrote:
> Brian E Carpenter <brian.e.carpenter at> wrote:
>> What are the causes of poor behaviour for IPv6-enabled users
>> in addition to 6to4 anycast brokenness?
> My colleagues have been having some problems debugging a 6in4 tunnel that
> has MTU problems - the ICMP too big / fragmentation needed packets aren't
> getting through and we aren't sure whether the problem in inside or
> outside the tunnel.

Yes, MTU discovery is a problem for most if not all tunnel solutions,
and even for native v6 in some cases (where one end has jumbo frames).
It is one of the possible causes for 6to4 woes, but it is not


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