Publishing LDAP server information in DNS

If DNS is to be used to publish LDAP server information, the relevant DNS name server or servers must be configured with the appropriate SRV and TXT records that reflect the LDAP servers available in the enterprise. SRV records are used to identify the LDAP servers in the enterprise along with appropriate priority and weight values. TXT records are associated with each LDAP server host to specify the LDAP URL used to access the LDAP server on that host and to provide information about the capabilities of the LDAP server. If SRV records are not supported by the DNS name server, TXT records can be used to emulate the SRV records or a CNAME record can be used to point directly to a single LDAP server host.

Domain name service resource names have a maximum length of 255 characters and use the ISO8859-1 code page. LDAP converts character parameters that are supplied by the application from the local EBCDIC code page to the ISO8859-1 code page when sending a request to the domain name server, and then converts the name server response from the ISO8859-1 code page back to the local EBCDIC code page when returning the results to the application.

The domain name server list must either contain the name server that is authoritative for the zone containing the LDAP server information, or one of the domain name servers in the list must support recursion and forward the query to the authoritative name server.

The DNS lookup routine ignores unrecognized TXT records and TXT records containing syntax errors.