Re: Character set support in LDAP

Mark Wahl (
Wed, 04 Sep 1996 17:15:22 -0500

> I would like to know which character sets (T.61, IA5 etc.) are
> supported for attribute values in LDAP. Is there support for
> T.61 at all? And Unicode?

In LDAP version 2, string attribute values are in T.61, except for those which
are restricted to a PrintableString or IA5 syntax. In LDAP version 3, most
string values are in the UTF-8 encoding of Unicode instead of T.61.

A list of the attributes' syntaxes in LDAPv2 is given in Section 4.1 of
<draft-ietf-asid-ldapv2-attributes-00.txt>. The "caseIgnoreString" syntax
syntax is T.61.

A list of the attributes' syntaxes in LDAPv3 is given in Section 5.1.1 and
5.1.2 of <draft-ietf-asid-ldapv3-attributes-02.txt>. The "DirectoryString"
syntax is UTF-8.

The Umich LDAP 3.3 release includes library routines for a lossy conversion
between T.61 and ISO 8859-1 in a client.

A description of the UTF-8 algorithm is available from
A pointer to this description and sample conversion code is on the page

Hope this helps,

Mark Wahl, Enterprise Directory Integration
Critical Angle Incorporated