ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
		BasicConstraintsValid: true,
	}

	hosts := strings.SplitSeq(host, ",")
	for h := range hosts {
		if ip := net.ParseIP(h); ip != nil {
			template.IPAddresses = append(template.IPAddresses, ip)
		} else {
			template.DNSNames = append(template.DNSNames, h)
		}
	}

	template.IsCA = true