Google filtering ICMPv6 type 2?

[Erik Kline]

>> I don't know you're exact setup but in the meantime you might set the
>> MTU in the RA for hosts behind that tunnel; that way they know their
>> correct MSS...
>
> They're actually a few hops away from the tunnel in both test cases,
> connected by GigE, so the MSS is correct for their local interfaces.  I
> suppose I could change everything to 1280 on the links via radvd, but by
> then I'm sure things will be long resolved.. :-)

Right.  And we could force 1280 on our end, with the same result.  The
general feeling at the moment is that if we can get/keep pMTUd working
then that's better than just clamping everything at 1280.