I have several networks which are on Comcast's residential network. I need to access those networks from a variety of environments, via an SSH proxy on one of the hosts.
(As it happens I'm using OpenWRT, so a specific solution there would be helpful; but I'm also generally curious how one does this with any Linux or BSD-based edge routing solution.)
With IPv4, this is relatively straightforward: since all my internal IPs are allocated with DHCP, I can simply set up a forwarding rule to move port 22 on the external interface to port 22 on a specific IP.
Since my IPv6 addresses are all allocated with SLAAC, I don't have a static address that I can use in ip6tables-land to forward things.
How can I detect changes to the prefix allocation so that I can establish new iptables rules? Or is there a way to set up a rule which forwards to a particular host based on discovering its IP address from its MAC address or something like that? (These hosts are all on a single segment so multicast and such should work.)