I have RB1100AHx2 with latest RouterOS v6.29.1 and I have working IPv4 setup. I need to add IPv6 support.
I’v got 2001:0db8::10/127 for the upstream provider interface and 2001:0db8::11/127 for mine.
The provider I’m talking about is Cesnet in the Czech republic, which is the provider for academic network and this network works on IPv6 for looong time (they use Cisco routers).
So I did:
/add address=2001:0db8::11/127 advertise=no interface=eth0
/add distance=1 gateway=2001:0db8::10
It did not worked (but I saw incoming ICMP packets) because the gateway was unreachable and I read that it seems to be impossible to use /127 prefix on Mikrotik even RFC exists (I read some posts here, for example http://forum.mikrotik.com/t/ipv6-127/71778/1).
So I tried /126 prefix, but the gateway is still not active in the routing table and Winbox UI shows me “unreachable” even this should be Ok (at least by network subnet math) and no “A” is printed and ping tells me “network unreachable”:
/ipv6 route print
Flags: X - disabled, A - active, D - dynamic, C - connect, S - static, r - rip, o - ospf, b - bgp, U - unreachable
DST-ADDRESS GATEWAY DISTANCE
0 S ::/0 2001:db8::10 1
I have to use /123 at least to get it working (the “A” appears and ping start to work, ICMP replies are sent out).
Or I have to use link-local address for default gateway (it works even with /127 or /128 prefix with my local IPv6 address) but I dislike this as the IPv6 link-local addres could be changed without prior notice from my ISP:
/add distance=1 gateway=fe80::a2f3:e4ff:febb:5357%eth0
It seems like /126 could not be used because of a bug in ROS. Or I did a mistake somewhere?
ADDENDUM: I created a route between 2001:db8:ff::1/126 and 2001:db8:ff::2/126 and it works Ok.
It seems to me like using a route to “network address” (ie. route with all-zeroes in the place for host number, which means interface identifier) is not possible in Mikrotik. If this is true, this makes strong trouble with Mikrotik interoperability (ie. connectivity with Cisco because Cisco is able to work with /127 prefix).