IPv6 router advertisement not working

RouterOS General
1

(Sorry if this has been asked before, I’m getting too many false hits while searching.)

I have a RB750GL running 6.37.1.

Long story short, I thought IPv6 advertisements were working for the bridged interface ether2. I turned on Wireshark from my Mac laptop and found out the router advertisement is actually coming from a Cisco device I’ve been playing with.

The odd thing is I think advertisements are working on a vlan interface (separate layer 2 domain) from the RB750GL with only a few IPs and it’s not bridged to any other interface. I haven’t put Wireshark on it but there are no devices that should be acting as routers other than the RB750GL on that layer 2 network.

If I turn off the Cisco device and watch Wireshark, the only thing coming from anybody to FF02::1 are MNDP packets from a few MikroTik devices on that layer 2 network.

Can someone point me to RA troubleshooting documentation or maybe some common problems? It’s entirely possible that I have some configuration problem causing this but I haven’t found it.

2

Update. If I go to “ipv6 nd prefix” and look there, it shows the prefix for the bridged interface is invalid. The previx for the vlan interface is not invalid. I don’t know why this is.

Thanks.

3

Could you post the output of the following command:

/ipv6 export
4 
/ipv6 address
add address=fd9c:944d:aa3:3342:192:168:0:254 interface=ether2-master-local
add address=fd9c:944d:aa3:1000:10:99:0:1 advertise=no interface=andy-xxx-gre
add address=fd9c:944d:aa4:3342:172:16:1:1 interface=vlan4
/ipv6 firewall filter
add action=drop chain=input in-interface=ether1-gateway
add action=drop chain=forward in-interface=ether1-gateway
/ipv6 nd
set [ find default=yes ] interface=ether2-master-local
add interface=vlan4 ra-lifetime=none
5

Maybe it has something to do with the following (at least, I had this issue in a simular situation).
You have two IPv6 addresses that are in the same /64 (fd9c:944d:aa3:3342:192:168:0:254 and fd9c:944d:aa4:3342:172:16:1:1)
Could you try to make the fd9c:944d:aa4:3342:172:16:1:1 a /128 and check if the invalid flag disappears?
If not, maybe try to set that address to not advertise as well.

If that works, then you at least know in which direction you have to look for.

6

They actually aren’t in the same /64, one is aa3, the other is aa4.

If I change the address to /128 or just delete it, I get no change. ipv6 nd prefix still shows invalid for the one that ends in 254.

Almost seems like a bug.

7

Sorry, my bad…just got out of bed lol.

8

I have an update on this.

I have a hAP AC Lite router that was also showing under ipv6 nd prefix that the prefix was invalid. I reset the configuration, set it up again, and now it works.

This really seems like a bug. I’m not sure what I can do to make a prefix invalid if it’s the only prefix that exists.

I’m going to work on my RB750 now to see if I can fix it.