Overview#

Differences between LDAP 2 and 3 Protocols

The most obvious differences between the two LDAP versions are in the LDAP Message and LDAP Result structures. LDAPv3 has replaced the Search Response field with these new fields.

• SearchResultEntry
• SearchResultDone
• SearchResultReference

The Search operation uses the extendedResp field if the original LDAP Message used the extendReq field.

LDAPv3 LDAP Result added these new fields:

• referral (10)
• adminLimitExceeded (11)
• unavailableCriticalExtension (12)
• confidentialityRequired (13)
• saslBindInProgress (14)
• affectsMultipleDSAs (71)

LDAPv3 adds the following features to LDAP which were not available in LDAPv2:

• Strong authentication and data security services via SASL
• Certificate authentication and data security services via TLS (SSL)
• Internationalization through the use of Unicode (UTF-8)
• LDAP Referrals and Continuations
  • In LDAPv2 servers are supposed to handle LDAP Referrals and not return them to the client. (Chaining)
• LDAP Schema Discovery Mechanism
  • In LDAPv2 had little consistency within the LDAP Schema
• Extensibility (SupportedControl, Extended Request operations, and more)
  • In LDAPv2 the only common field was the Message ID. LDAPv3 adds a common SupportedControl field so that the LDAP protocol can be extended.
• Modrdn would only rename an entry with the same context. To move an entry it needed to be deleted and then use an Add Request
• OperationalAttribute was not available in LDAPv2

More Information#

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

• LDAPv3

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• [#1] - Differences between LDAP 2 and 3 Protocols - based on information obtained 2019-03-19