DomainComponent (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:

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 DomainComponent AttributeTypes is defined as in RFC 4519:


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'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 DomainComponent label. The special considerations discussed in Section 4 of RFC 3490 should be taken, depending on whether the DomainComponent is used for "stored" or "query" purposes.

More Information#

There might be more information for this subject on one of the following: