My grandparent's crappy ISP-sponsored router from ~2017 (maybe 2016), TP-Link C1200 v1, had the IPv6 firewall enabled by default. (It has UPnP enabled by defaul

My grandparent's crappy ISP-sponsored router from ~2017 (maybe 2016), TP-Link C1200 v1, had the IPv6 firewall enabled by default. (It has UPnP enabled by default too... which I turned off promptly. They don't need it anyway.) My own Asus router from 2016, RT-AC1200G+, also came with IPv6 firewall enabled. Both routers are 8 years old at this point. And they are far from being a prosumer product. What router are you using that it doesn't come with IPv6 firewall enabled? edit: Oh, and my friend's cheapo Netis router (quite an obscure brand IMO) also had IPv6 firewall enabled out of the box. >ipv6 firewalls to become ubiquitously strong They don't need to be strong, the firewalls just have to be stateful so that they can drop unsolicited packets. It's that simple. Any other more sophisticated attacks would have made your NAT equally vulnerable as well. Additionally, stateful firewalls have been available since decades ago. They are not exactly black magic.