!!! Overview
[{$pagename}] ([DC] in [RFC 1274]) [AttributeTypes] is a [string] holding one component, a label, of a [DNS Domain] name [RFC 1034] [RFC 2181] naming a host [RFC 1123].  

That is, a value of this attribute is a string of [ASCII] characters adhering to the following [ABNF] [RFC 4234]:
%%prettify 
{{{
label = (ALPHA / DIGIT) [*61(ALPHA / DIGIT / HYPHEN) (ALPHA / DIGIT)]
ALPHA   = %x41-5A / %x61-7A     ; "A"-"Z" / "a"-"z"
DIGIT   = %x30-39               ; "0"-"9"
HYPHEN  = %x2D                  ; hyphen ("-")
}}} 
/%

The encoding of [IA5String] for use in [LDAP] is simply the characters of the [ASCII] label.  The [EQUALITY] [Matching Rule] is [Case-insensitive], as is today's [DNS].  (Source: [RFC 2247] and [RFC 1274])

!! [LDAP] [Attribute] Definition
The [{$pagename}] [AttributeTypes] is defined as in [RFC 4519]:
* [OID] of [0.9.2342.19200300.100.1.25] 
* [NAME|Attribute-Name]: [{$pagename}] [DC]
* [DESC]: 
* [EQUALITY]: [caseIgnoreIA5Match]
* [SUBSTR]: [caseIgnoreIA5SubstringsMatch]
* [ORDERING]: []
* [SYNTAX]: [1.3.6.1.4.1.1466.115.121.1.26]
* [SINGLE-VALUE]
* [USAGE]: [UserApplications] 
* [Extended Flags]: 
** [X-ORIGIN]: [RFC 4519]
* Used as [MUST] in:
** [domain]
** [dcObject]
** [nisDomain]
* Used [MAY] in:
**


!! [Examples]
Valid values include "example" and "com" but not "example.com".  The latter is invalid as it contains multiple domain components.

It is noted that the [Directory Service] will not ensure that values of this attribute conform to the host label restrictions [RFC 1123] illustrated by the <label> production provided above.  It is the [directory client|DUA]'s responsibility to ensure that the labels it stores in this attribute are appropriately restricted.

Directory applications supporting International Domain Names [SHALL] use the ToASCII method [RFC 3490] to produce the [{$pagename}] label.  The special considerations discussed in Section 4 of [RFC 3490] should be taken, depending on whether the [{$pagename}] is used for "stored" or "query" purposes.


!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]