As a CA, you may sign a certificate for anything. Public CAs don't do it for IPs for obvious reasons, but if you're cloudflare or Google, you can coax them with

As a CA, you may sign a certificate for anything. Public CAs don't do it for IPs for obvious reasons, but if you're cloudflare or Google, you can coax them with enough money and goodwill to sign a cert for your very expensive quad-single-digit ip, especially if you manage to motivate that request with the fact that the IP is a DNS resolver and can't be pointed at by a domain in the first place