LDAP initialization and configuration

Guru-host is able to deploy any setup of the Lightweight Directory Access Protocol based on OpenLDAP and any Linux distribution or Sun Solaris Operating System. We can deploy from simple one machine installations up to many load balanced, fail over OpenLDAP master/slave servers. If you have no idea about OpenLDAP and you are looking for a way to share same username and password accross your company then this is the place for you! Below you will find a brief overview of what LDAP/OpenLDAP is and when it is a must to use it. Since May 2010 we are able to offer configurations based on Redhat Directory Server too. Just contact us to discuss your requirements.

What is a directory service?

A directory is a specialized database specifically designed for searching and browsing, in additional to supporting basic lookup and update functions. A directory is defined by some as merely a database optimized for read access. This definition, at best, is overly simplistic.

Directories tend to contain descriptive, attribute-based information and support sophisticated filtering capabilities. Directories generally do not support complicated transaction or roll-back schemes found in database management systems designed for handling high-volume complex updates. Directory updates are typically simple all-or-nothing changes, if they are allowed at all. Directories are generally tuned to give quick response to high-volume lookup or search operations. They may have the ability to replicate information widely in order to increase availability and reliability, while reducing response time. When directory information is replicated, temporary inconsistencies between the replicas may be okay, as long as inconsistencies are resolved in a timely manner.

There are many different ways to provide a directory service. Different methods allow different kinds of information to be stored in the directory, place different requirements on how that information can be referenced, queried and updated, how it is protected from unauthorized access, etc. Some directory services are local, providing service to a restricted context (e.g., the finger service on a single machine). Other services are global, providing service to a much broader context (e.g., the entire Internet). Global services are usually distributed, meaning that the data they contain is spread across many machines, all of which cooperate to provide the directory service. Typically a global service defines a uniform namespace which gives the same view of the data no matter where you are in relation to the data itself.

A web directory, such as provided by the Open Directory Project , is a good example of a directory service. These services catalog web pages and are specifically designed to support browsing and searching.

While some consider the Internet Domain Name System (DNS) is an example of a globally distributed directory service, DNS is not browseable nor searchable. It is more properly described as a globally distributed lookup service.

What is LDAP?

LDAP stands for Lightweight Directory Access Protocol. As the name suggests, it is a lightweight protocol for accessing directory services, specifically X.500-based directory services. LDAP runs over TCP/IP or other connection oriented transfer services. LDAP is an IETF Standard Track protocol and is specified in "Lightweight Directory Access Protocol (LDAP) Technical Specification Road Map" RFC4510.

This section gives an overview of LDAP from a user's perspective.

What kind of information can be stored in the directory? The LDAP information model is based on entries. An entry is a collection of attributes that has a globally-unique Distinguished Name (DN). The DN is used to refer to the entry unambiguously. Each of the entry's attributes has a type and one or more values. The types are typically mnemonic strings, like "cn" for common name, or "mail" for email address. The syntax of values depend on the attribute type. For example, a cn attribute might contain the value Babs Jensen. A mail attribute might contain the value "babs@example.com". A jpegPhoto attribute would contain a photograph in the JPEG (binary) format.

How is the information arranged? In LDAP, directory entries are arranged in a hierarchical tree-like structure. Traditionally, this structure reflected the geographic and/or organizational boundaries. Entries representing countries appear at the top of the tree. Below them are entries representing states and national organizations. Below them might be entries representing organizational units, people, printers, documents, or just about anything else you can think of. Figure 1.1 shows an example LDAP directory tree using traditional naming.

Posted on: 31/05/2010