Public IP addresses are supported on GlobalSign’s OrganizationSSL certificates. Other variations, such as DomainSSL & ExtendedSSL, do not support the securing of an IP address. While an IP address can be specified as a common name or as a Subject Alternative name, there are compatibility factors that should be taken into account before deciding how to order.
If you are targeting Windows 10 & later, you can populate the IP address in either field. If however, you are targeting Windows 8.1 & earlier, you should only specify the IP address as the common name.
Order to maintain compliance with RFC 5280, subject alternative names have a value that specifies the content type. For example, a SAN for www.example.com would be specified as dNSName & a SAN for 123.456.78.90 would be specified as iPAddress. Proper handling for the iPAddress SAN type was added in Windows 10, versions prior to this will not process iPAddress SANs properly.
For this reason, if you need to target Windows versions prior to 10, order the certificate with the desired IP address as the common name; earlier versions of Windows will validate from the common name instead of the iPAddress SAN entry.