Re: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms

Hey Jean,

I confess using IPv6 behind a 6in4 tunnel because the "Business-Class" service of the concerned operator doesn't handle IPv6 yet.

as such, I realised that, as far as I can figure, ICMPv6 packet "too-big" (rfc 4443) seem to be ignored or filtered at ~60% of ClouFlare's http farms

Might be related to this: https://blog.cloudflare.com/path-mtu-discovery-in-practice/ If you run ECMP then the hash algorithms make no guarantees ICMP messages generated by transit devices reach the correct host. -- ++ytti