As mentioned previously, LDAP queries are not much like SQL queries. Therefore, the syntax may seem a bit limiting, but here is a basic example and one that works in this scenario.

//Create Query
$ldap_query = "cn=$common";

In our example "cn" is the attribute on which we are performing the search, and $common is the search string variable from the search form. LDAP query syntax allows for wildcard matching using '*'. For example, '*stanley' will find 'dan stanley'.

The given function connects to an LDAP resource and assigns the connection link identifier to a variable, much like connecting to a regular database, like MySQL.

In our example, "$connect_id" is the link identifier, $LDAP_SERVER is the array of possible ldap servers, and $SERVER_ID is the LDAP server variable from the search form.

If our connection was successful, we will have a valid LDAP link identifier and we can process the query.

Once we have established a connection to the LDAP services, we must identify ourselves. Most database connections with PHP send the username and password with the connection. However, with LDAP, credentials are unknown until a bind is performed. In our example, "$bind_id" is the bind link identifier. We are performing an anonymous bind to the public LDAP servers. Therefore, no argument is sent to ldap_bind() accept the connection link identifier.

After we have been authorized, via bind as anonymous, we perform the query using the ldap_search() function. $search_id is created and is our search link identifier.

Then, we assign our result set to the variable $result_array using the function ldap_get_entries(). This will allow us to sort the information in a logical manner for display.