!!! Overview
[{$pagename}] ([OID] [2.5.29.17]) ([subjectAltName] or [SAN]) [attribute] is an [Certificate Extensions] to [X.509] that allows additional [Certificate Subject] names to be associated with [certificate].[1] If the [Certificate Authority] issues certificates with an empty sequence for the [Certificate Subject], the CA [MUST] support the [Subject Alternative Name] [Certificate Extension]

[{$pagename}] [MAY] include:
* [Email] addresses
* [IP Address] 
* [URIs]
* [DNS] names (alternatives to the [Common Name])
* directory names (alternatives to the [Distinguished Names])
* other objects, given as a registered [Object Identifier] followed by a value

!! [{$pagename}] and [IP Address]
[RFC 5280] section 4.2.1.6 specifies [iPAddress] alternative name format, designed to hold dotted quads ([IPv4]) or 16 octets ([IPv6]). 

[Browser]/[client] compatibility will vary.

You can specify a dotted quad in a [dNSName] field of the SAN. To quote [RFC 5280]:\\
''The name MUST be in the "preferred name syntax", as specified by Section 3.5 of [RFC 1034] and as modified by Section 2.1 of [RFC 1123]
The latter suggests that software should be tolerant of finding IP addresses in "host name" fields:''

Whenever a user inputs the identity of an Internet host, it [SHOULD] be possible to enter either 
* (1) a host domain name or 
* (2) an IP address in dotted-decimal ("#.#.#.#") form. 
The host [SHOULD] check the string syntactically for a dotted-decimal number before looking it up in the [Domain Name System].

Please note also that, per [RFC 5280]:
Because the [dNSName] is considered to be definitively bound to the [Public Key], all parts of the [{$pagename}] [MUST] be verified by the [CA].

When we last checked, the following __IGNORED__ [IP Address] and expect the value as string in [dNSName]:
* MSIE and MS Edge 
* Python 2.
but:
* [Chrome]
* [Safari]
* [Firefox] 
do not expect an [IP Address] as [dNSName] but need it as [iPAddress]. 

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }] 
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* [#1] - [SubjectAltName|http://en.wikipedia.org/wiki/SubjectAltName|target='_blank'] - based on 2013-11-18