Because on my real routers I do not keep the default ND entry enabled and always create individual entries for the interfaces where RA is needed, so I am not affected by this and don't want to spend the time to create a support ticket and have to handle all the waiting? But even in the 7.23 release thread, enough people have reported the problem and I thought MikroTik staff does follow the release threads? Here a some sample threads for you:
- This huge one which at the beginning no one knew
/ipv6 ndwas the real cause: Problem with DHCP in 7.23rc when used behind Rogers' modem in Canada - RouterOS / General - MikroTik community forum - In the 7.23.1 thread 7.23.1 [stable] is released! - Announcements - MikroTik community forum.
- Another IPv6 Nieighbor Discovery for Bridge Advertises Invalid IPv6 Default Route - RouterOS / General - MikroTik community forum.
- More [7.23.1] Invalid IPv6 prefixes after update from 7.22.3 - RouterOS / General - MikroTik community forum.
I did packet capture back then with my test CHR installations. After your comment today, I repeated the test and can now point out to you the real cause why it affected so many people. Do this in your LAB:
- Pick any device, including CHR
- Put 7.20.8 on it. It can be any version <= 7.20.x, but the download link to 7.20.8 can still easily be found on the the "long term" download page without having to manually edit the URLs.
- Reset the configuration, you can even reset to a blank configuration if you want.
- Observe with any packet capture software that the router does not send RA on any interfaces.
- Switch / upgrade to the latest stable 7.23.2.
- Observe that the device now sends RA on all of its interfaces.
And here is the real reason. Before 7.21, before this change:
This is the default state of the default /ipv6 nd entry. The state when /ipv6 nd export produced no output at all:
That's what everyone who have never tinkered with the default IPv6 ND entry would have!
The upgrade to >= 7.21 will convert that to this:
We can say that this is a problem that the majority of device owners who bought their devices before 7.21 (which was released less than 6 months ago) and have not reset the configuration after 7.21+ will have, and MikroTik has to address that!
You should really revert the 7.23 change (the functionality provided by 7.21 is already enough), because there are certainly many long-term users who have upgraded to 7.21.5 and have the dormant
/ipv6 nd
set [ find default=yes ] advertise-dns=yes
on their devices that will throw the problem to them once they upgrade to 7.23+ in the future.