wondering if this is possible.
I’m receiving a /56 from my ISP which I split in /60 pools because I do have a downstream router that runs another delegation from one of these.
Now, for a smaller side network, I’d like to assign a /64 address to a hardware port, running SLAAC.
Terminal lets me select a /64 even though the pool it’s to be generated from is /60 … as long as I set advertise=yes which I do need for SLAAC anyways.
Wondering if this leads to an address chain without valid gateway?
When router advertises a prefix, it’ll advertise its own IPv6 address with it. And AFAIK it’ll advertise it’s LL address (but I may be wrong here). What remains to be seen (run a wireshark on a client device and check the RA packets) is whether router actually advertises /64 prefix even though the address was taken from pool which hands out /60 prefixes.
OTOH I don’t know if it’s worth bothering: as soon as you take one address from pool, pool will mark the whole prefix as taken (in your case /60). And it doesn’t matter if you use it as /64 (or /96 or whatever). So you can’t get another address from pool which would fall into same /60 prefix. Which means that you might use /60 prefixes (for that subnet) as well because from pool utilization point of view, you can’t optimize it.
Unless you somehow work around it and manually set other IPv6 addresses (which would fall into same /60 prefix, but you use them as /64 addresses) … but that is done behind “pool’s back”.
I’ll look into the traffic as soon as my other smaller issues are done with
I would just use a /60 prefix, but RouterOS won’t let me You can only set advertise for an address with a /64 prefix.
Thus, my guess is that RouterOS blocks one full /60 pool, takes a /64 subnet from it and advertises this.
Advertising shorter prefixes would require a DHCP-PD-Server.
At least that’s what I have found out in the last days…
