Other replies explained the why, though cgnat wouldn’t be a problem if you also had ipv6.
Luckily for me I have a regular ip4 address but if that ever changed I’d be out of luck unless my isp (quantum fibre) implemented a proper ipv6 solution.
That uses 6rd which is typically slow (since it basically proxies through an ipv4->6 bridge), and in my case it worked on their provided router but not with opnsense.
Luckily for me I have a regular ip4 address but if that ever changed I’d be out of luck unless my isp (quantum fibre) implemented a proper ipv6 solution.