Hi,

we are using a Mikrotik CCR (v6.24) as PPPoE Server providing IPv4 & IPv6 via IPv6-PD. This is actually working very nice with customers that are using home routers from AVM (Fritzbox).

The problem is that there are some strange effects - not allways but often, that occure when websits are delivered using IPv6. Facebook loading partitially and/or slowly, 3 days ago all google sites suddenly failed to load at all in 90 % of the cases. Before there has not been any issue with google & IPv6.
We turned off IPv6 now until this is solved.

The problem does not occure an a server that is connected to the Mikrotik without PPPoE.

On this server I can do ping6 up to 1452 bytes (+48 byte header = 1500)
# ping6 -s 1452 -c 3 ipv6.google.com
PING ipv6.google.com(fra02s21-in-x0e.1e100.net) 1452 data bytes
1460 bytes from fra02s21-in-x0e.1e100.net: icmp_seq=2 ttl=55 time=10.7 ms

On a PPPoE Client I can only do a max. paket size of 1232 (+48 = 1280 - minimum MTU on IPv6)

Maybe this is where the problem originates from. But on the PPPoE Interface of the Mikrotik Router there is nothing to setup concerning IPv6 MTU.

Is anyone familiar with this kind of issue?