Not common, but there is the use case of vanity IPs. The cert for https://1.1.1....

		teaearlgraycold 57 days ago \| parent \| context \| favorite \| on: Getting ready to issue IP address certificates Not common, but there is the use case of vanity IPs. The cert for https://1.1.1.1 is signed for the IP as well as the domain name one.one.one.one