On 6 Jul 2011, at 22:52, Sabahattin Gucukoglu wrote: On 6 Jul 2011, at 19:03, james woodyatt wrote: >> You're invited to file a report with <http://bugreport.apple.com> about this. Be sure to explain why fixing the broken path MTU discovery in the network is not an option and requiring the AirPort user to know enough about IPv6 router advertisement MTU options to set the value properly is an appropriate mitigation. > > Thank you, and what should the severity of the bug be? This is bug #9739722, Airport: Configurable IPv6 RA link-MTU or MSS Clamping. Severity 2. Hurricane Electric very generously lowered my tunnel's MTU to 1476 bytes IPv6 payload, so I'm now back on the IPv6 Internet again. (Yay!) There is still one important detail to clear up, though. My ISP, BT Infinity Business in the UK, seems to be ensuring that its links do not overflow by "Clamping" the MSS option in TCPv4 SYN packets to 1400, and no sight of ICMPv4 "Datagram too large and DF set" messages. Can I take it for granted that you didn't choose the same value, or do a similar terrible thing, in the Airport products? I don't have any other PPPoE servers to try it on. Cheers, Sabahattin _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf