However, some organizations need an SSL certificate for a public IP address. GlobalSign offers support for IP addresses on SSL certificates both in the common name and Subject Alternative Name (SANs) fields.
rfc5280:
http://www.rfcreader.com/#rfc5280
4.2.1.6. Subject Alternative Name URIs that include an authority ([RFC3986], Section 3.2) MUST include a fully qualified domain name or IP address as the host