I have managed to find references that say that IPv6 works with openvpn in ethernet mode (
http://forum.mikrotik.com/viewtopic.php ... 26#p187333), it would be good to get a definitive answer.
What I have found is that the tunnel seems to be established without a problem, and IPv4 works. The IPv6 address that is sent by the openvpn server is ignored by routeros, but routeros will happily let you assign the IPv6 address to the tunnel interface, and at this point IPv6 works fine... but...
IPv6 traffic only flows when traffic is flowing from the ovpn-client to the openvpn server. If an attempt is made to ping the client from the server, you get "Address unreachable". As soon as traffic (such as another ping) starts flowing from the client to the server, the ping from the server to the client magically starts working.
[root@257233-app1 openvpn]# ping6 2001:4800:xxxx:xxx:8000::3
PING 2001:4800:xxx:xxx:8000::3(2001:4800:1020:395:8000::3) 56 data bytes
From 2001:4800:xxxx:xxx::7a25 icmp_seq=1 Destination unreachable: Address unreachable
From 2001:4800:xxxx:xxx::7a25 icmp_seq=2 Destination unreachable: Address unreachable
From 2001:4800:xxxx:xxx::7a25 icmp_seq=3 Destination unreachable: Address unreachable
From 2001:4800:xxxx:xxx::7a25 icmp_seq=5 Destination unreachable: Address unreachable
From 2001:4800:xxxx:xxx::7a25 icmp_seq=6 Destination unreachable: Address unreachable
From 2001:4800:xxxx:xxx::7a25 icmp_seq=7 Destination unreachable: Address unreachable
64 bytes from 2001:4800:xxxx:xxx:8000::3: icmp_seq=8 ttl=64 time=200 ms
64 bytes from 2001:4800:xxxx:xxx:8000::3: icmp_seq=9 ttl=64 time=114 ms
64 bytes from 2001:4800:xxxx:xxx:8000::3: icmp_seq=10 ttl=64 time=114 ms
64 bytes from 2001:4800:xxxx:xxx:8000::3: icmp_seq=11 ttl=64 time=114 ms
64 bytes from 2001:4800:xxxx:xxx:8000::3: icmp_seq=12 ttl=64 time=114 ms
64 bytes from 2001:4800:xxxx:xxx:8000::3: icmp_seq=13 ttl=64 time=114 ms
--- 2001:4800:xxx:xxx:8000::3 ping statistics ---
14 packets transmitted, 6 received, +6 errors, 57% packet loss, time 13002ms
rtt min/avg/max/mdev = 114.556/129.010/200.484/31.966 ms, pipe 2
Is IPv6 fully supported in RouterOS 6?