Yes, I don’t want to be hasty, but it seems to work. Manualy set MAC address of the bridge interface do this.
WIN!
So, I can really confirm, that manually set MAC address of the bridge is a functional workaround for missing Advertisement packet issue. BUG IN ROUTEROS REMAINS.
Now that I think about it, I wouldn’t call it a bug, per se. I think my assertion of it as an undocumented feature would be more accurate, though it was only in jest when I initially brought it up.
I celebrated too early. It suddenly stop to work. No advertisement packets anymore. I have to restart br0 interface to get packets again.
That’s a bug. You need to email mikrotik with a supout.
So bug still exists in ROS 4.6. No response from support for more than three weeks. 
I am experiencing the same issues with support on another, somewhat related, ticket. Where’d you go mikrotik?
Yes, this is a big problem. Thus I am unable to use IPv6 in my networks for months. IPv6 implementation in ROS seems to be buggy.
So, I have tried to get IPv6 work with ROS 4.7, but still without any success. Still no RA packets in my network, still no IPv6 In ROS 4.7 is my advertised prefix marked as invalid in Neighbor Discovery window ( has flags Dynamic, Invalid). I don’t know why?
0 ID prefix=2001:470:1f15:692::/64 interface=br0 on-link=yes autonomous=yes valid-lifetime=4w2d preferred-lifetime=1w
I did some more test. But I have to confirm that Router Advertisement at bridge is still broken. I managed to get it work, but it works only for certain time. It looks like there are no RA packets after the midnight 
Than I have to restart the router.
Did you try to enable radvd logging? It shows if ROS is trying to send something or not.
Few times I had similar problem as you describe in your first post. It happened only when I tested other things and unplugged ethernet cable from RB. Then sometines after plugging it back, RAs didn’t come any more. And with radvd logging enabled it wrote some errors, but I don’t remember what exactly it was. RB reboot fixed that.
As for bridge, I have one for OpenVPN clients to give IPv6 addresses to them and it works fine, no missing RAs yet.
Few times I also expirienced situation when RAs were coming, reached client computer, but OS (Win7) ignored them.
So I let ROS to send logs to my syslog and discovered this:
Apr 25 21:33:42 r4bu110 radvd,debug: radvd: sending Router Advertisement on br0
Apr 25 21:33:42 r4bu110 radvd,debug: radvd: adding link-layer address option, mac-address=01:00:00:00:01:00
Apr 25 21:33:42 r4bu110 radvd,debug: radvd: adding prefix=2001:470:1f15:692::/64
Apr 25 21:33:42 r4bu110 radvd,debug: radvd: sendmsg failed on br0 (fe80::20b:6bff:fedd:3463): Invalid argument
So radvd failed to send RA message on br0 interface, but why? Where is invalid argument?
Is this bug or my configuration error?
Later appeared this without any following error:
Apr 25 21:48:28 r4bu110 radvd,debug: radvd: sending Router Advertisement on br0
but no RA packed arrived. Wireshark confirmed this to me.
Any ideas? Thanks.
This isn´t just a RB450G related problem. I´ve got the same issues on all RB433AH and RB450G, too.
My work around is, to export the /ipv6/address stuff, delete all entries and reimport them. This works for me until I do some mandatory changes.
Yesterday my ROS6.4 drove me crazy:
It filtered IPv6 traffic on a bridged interface. I removed the bridge, done all configuration absolutely right, but it doesn´t route IPv6 traffic anymore. The router it self can ping global destinations but any host behind the router can´t. A traceroute goes to the router but then ends without success. The firewall has got a rule which allows all packets to be forwarded on any interface.
Any ideas?
Best regards
Stefan
I have got RB433AH and the behavior is same as in case of RB450G. So this seems to be a general problem of all RBs.
The must be a bug in the RADVD daemon, because it claims that RA packet has been sent but no packet appears in Wireshark.
Devs, please provide some fix. RA is key feature of IPv6. I can’t use IPv6 without RA.
+1
We had this problem with version 4.6. Upgrading to version 5.0 beta solved it.
Another important problem we had with version 4.6 is that ARP was not working with vrrp like mac address on the network. We had no connectivity at all with the main routers, who have vrrp interfaces. Eth1 was not working if i remember well, we had to use eth2. We downgraded to version 4.4 as well to solve the problem. We loosed three hours at night in the datacenter because of this, and we loosed some trust with Mikrotik RouterOs. So we are now extending the testing period to 6 monthes before to enter production.
I think that Ros has become to much complicated compared to the Mikrotik staff programming and testing power.
It’s time to make the software opensource Mikrotik guys… And concentrate about hardware sellings. Or pay new master programmers.
Every new versions of it introduce new problems. See the latest 4.7 and 4.8 versions.
I’m afraid by futur versions with full IPv6 support, if we still have many basic problems with IPv4.
But Mikrotik RouterOS is the best for the price. No problem here :=)
Hi,
disabling the address and reenable it, fixes this problem for a while. But after some time, the problem reappears.
Best regards
Stefan
PS: My IPv6 trouble is solved now, thanks Lev.
I tried to disable/enable interface and export/import settings. It works, but only until midnight After the midnight there are no more RA packets.
I know that 5.0 beta solve this bug, but I don’t dare to install 5.0 beta at production routers. Hope that fix will be back ported to the 4.xx branch. Until that - no IPv6.
Martin
For me it doesn’t work until midnight. I had to do this action more than once today. This is really annoying, as i promoted and highly recommended the Mikrotik-Stuff on Microsoft Server Summit 2009 reloaded in an IPv6 session.