Comment by kstrauser

> in ipv4, if my laptop tries to use a printer with a public ipv4 address, that raises alarms.

The only way that’s possible is that you have a firewall rule blocking outbound connections to common printer ports like 631. NAT couldn’t care less what outbound port you’re connecting to, so it has to be a firewall doing that work.

> in ipv6, if my laptop tries to use a printer with an ipv6 address...

…so enable that same rule you manually configured on IPv4 on the IPv6 firewall, too.

What you’re describing is not default or inherent behavior. If you went out of your way to enable it, you have the skills to do it twice. That’s assuming your firewall is more complicated that “block outbound port <631> to <any IP>”, which covers both protocols on most firewalls I’ve used.