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Last updated: Tue, 19 Sep 2006


(PHP 4 >= 4.0.2, PHP 5)

ldap_compare -- Compare value of attribute found in entry specified with DN


mixed ldap_compare ( resource link_identifier, string dn, string attribute, string value )

Returns TRUE if value matches otherwise returns FALSE. Returns -1 on error.

ldap_compare() is used to compare value of attribute to value of same attribute in LDAP directory entry specified with dn.

The following example demonstrates how to check whether or not given password matches the one defined in DN specified entry.

Example 1. Complete example of password check


$ds=ldap_connect("localhost");  // assuming the LDAP server is on this host
if ($ds) {

    // bind 
    if (ldap_bind($ds)) {

        // prepare data
        $dn = "cn=Matti Meikku, ou=My Unit, o=My Company, c=FI";
        $value = "secretpassword";
        $attr = "password"; 

        // compare value
        $r=ldap_compare($ds, $dn, $attr, $value);

        if ($r === -1) {
            echo "Error: " . ldap_error($ds);
        } elseif ($r === true) {
            echo "Password correct.";
        } elseif ($r === false) {
            echo "Wrong guess! Password incorrect.";

    } else {
        echo "Unable to bind to LDAP server.";


} else {
    echo "Unable to connect to LDAP server.";


ldap_compare() can NOT be used to compare BINARY values!

Note: This function was added in 4.0.2.

Last updated: Tue, 19 Sep 2006