IPv6 Subnet behaviour

[CGGXANNX]

Yes, that is a known behavior of 7.21.x-7.22.x, introduced with this change:

@EdPa

• ippool6 - take into account "subnet-id" when specified on address;

Here I wrote about this behavior as well as the workaround for 7.21.x-7.22.x, which is to not use the zero-subnet-id for static assignment:

Experiences with ipv6?

You can specify the subnet id part since 7.21, no need to specify the full address. However there is one exception, that is the first subnet (the one with subnet id all zeros) cannot be specified that way, that one will be dynamic. You can read about this in the 7.21 threads. Example: ISP gives you /56 prefix, that you put in isp-pool, under /ipv6 address, you can assign hardcoded prefixes like this, together with from-pool=isp-pool: address=::1:xxxx:yyyy:zzzz:www address=::2:xxxx:yyyy:zzzz:w…

The issue is resolved in 7.23.x with help of a new parameter, I also have a post about it here:

Help with new features in v7.23(from-pool-policy)

The new manual has description for the possible values: address | RouterOS Manual You only see the effect when you try to assign the same subnet-id to multiple interfaces from the same pool. Here are some tests: /ipv6 pool add name=ula-pool prefix=fde8:b95b:6696:100::/56 prefix-length=64 /ipv6 address add interface=vlan20 address=::3:0:0:0:1/64 from-pool=ula-pool from-pool-policy=recommended add interface=vlan30 address=::3:0:0:0:1/64 from-pool=ula-pool from-pool-policy=recommended add i…

However, beware of the current issue with /ipv6 nd in 7.23.x. If you decide to install 7.23 or 7.24rc, you'll need to make sure the default /ipv6 nd with the all interface is either disabled or have options like DNS & MTU off / cleared.