On 2019-03-12 10:32, Nico Schottelius wrote:
Good morning,
is anyone from sbb.ch reading here?
https://sbb.ch does not load on IPv6 for us. It seems that packets > 1420 bytes are dropped inside the SBB network,
Local PMTU / fragmentation seems to work, my local outgoing MTU is 1420. MTR below.
Has been that way for years already.
Long live load balancers & firewalls and people who run them and do not know what they are or how they work.
Don't worry. Google had the same problem for a while and it took them a month or two to realize what the problem was and so did Cloudflare, at least the latter wrote it up so that other people can start getting the problem:
https://blog.cloudflare.com/increasing-ipv6-mtu/
Thus, folks, please read and start fixing your setups... ICMPv6 is required in IPv6 and when you do any kind of load balancing, do honor PTBs...
Greets, Jeroen