[hippich]

Assuming it is not trolling. Every time you get new IP from the ISP, you update DNS record for that domain. And browsers can connect to it to the exposed 80/443 port.

[xur17]

I believe GP's point is that some providers don't provide a publicly routable ip address.

[hippich]

Ah, haven't experience such thing yet. But if such thing happens, indeed it becomes way more complicated.