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Server Options

Each set of server options in the context of Zend_Auth_Adapter_Ldap consists of the following options, which are passed, largely unmodified, to Zend_Ldap::setOptions():

Table 10. Server Options

Name Description
host The hostname of LDAP server that these options represent. This option is required.
port The port on which the LDAP server is listening. If useSsl is TRUE, the default port value is 636. If useSsl is FALSE, the default port value is 389.
useStartTls Whether or not the LDAP client should use TLS (aka SSLv2) encrypted transport. A value of TRUE is strongly favored in production environments to prevent passwords from be transmitted in clear text. The default value is FALSE, as servers frequently require that a certificate be installed separately after installation. The useSsl and useStartTls options are mutually exclusive. The useStartTls option should be favored over useSsl but not all servers support this newer mechanism.
useSsl Whether or not the LDAP client should use SSL encrypted transport. The useSsl and useStartTls options are mutually exclusive, but useStartTls should be favored if the server and LDAP client library support it. This value also changes the default port value (see port description above).
username The DN of the account used to perform account DN lookups. LDAP servers that require the username to be in DN form when performing the "bind" require this option. Meaning, if bindRequiresDn is TRUE, this option is required. This account does not need to be a privileged account; an account with read-only access to objects under the baseDn is all that is necessary (and preferred based on the Principle of Least Privilege).
password The password of the account used to perform account DN lookups. If this option is not supplied, the LDAP client will attempt an "anonymous bind" when performing account DN lookups.
bindRequiresDn Some LDAP servers require that the username used to bind be in DN form like CN=Alice Baker,OU=Sales,DC=foo,DC=net (basically all servers except AD). If this option is TRUE, this instructs Zend_Ldap to automatically retrieve the DN corresponding to the username being authenticated, if it is not already in DN form, and then re-bind with the proper DN. The default value is FALSE. Currently only Microsoft Active Directory Server (ADS) is known not to require usernames to be in DN form when binding, and therefore this option may be FALSE with AD (and it should be, as retrieving the DN requires an extra round trip to the server). Otherwise, this option must be set to TRUE (e.g. for OpenLDAP). This option also controls the default acountFilterFormat used when searching for accounts. See the accountFilterFormat option.
baseDn The DN under which all accounts being authenticated are located. This option is required. if you are uncertain about the correct baseDn value, it should be sufficient to derive it from the user's DNS domain using DC= components. For example, if the user's principal name is, a baseDn of DC=foo,DC=net should work. A more precise location (e.g., OU=Sales,DC=foo,DC=net) will be more efficient, however.
accountCanonicalForm A value of 2, 3 or 4 indicating the form to which account names should be canonicalized after successful authentication. Values are as follows: 2 for traditional username style names (e.g., alice), 3 for backslash-style names (e.g., FOO\alice) or 4 for principal style usernames (e.g., The default value is 4 (e.g., For example, with a value of 3, the identity returned by Zend_Auth_Result::getIdentity() (and Zend_Auth::getIdentity(), if Zend_Auth was used) will always be FOO\alice, regardless of what form Alice supplied, whether it be alice,, FOO\alice, FoO\aLicE,\alice, etc. See the Account Name Canonicalization section in the Zend_Ldap documentation for details. Note that when using multiple sets of server options it is recommended, but not required, that the same accountCanonicalForm be used with all server options so that the resulting usernames are always canonicalized to the same form (e.g., if you canonicalize to EXAMPLE\username with an AD server but to with an OpenLDAP server, that may be awkward for the application's high-level logic).
accountDomainName The FQDN domain name for which the target LDAP server is an authority (e.g., This option is used to canonicalize names so that the username supplied by the user can be converted as necessary for binding. It is also used to determine if the server is an authority for the supplied username (e.g., if accountDomainName is and the user supplies, the server will not be queried, and a failure will result). This option is not required, but if it is not supplied, usernames in principal name form (e.g., are not supported. It is strongly recommended that you supply this option, as there are many use-cases that require generating the principal name form.
accountDomainNameShort The 'short' domain for which the target LDAP server is an authority (e.g., FOO). Note that there is a 1:1 mapping between the accountDomainName and accountDomainNameShort. This option should be used to specify the NetBIOS domain name for Windows networks, but may also be used by non-AD servers (e.g., for consistency when multiple sets of server options with the backslash style accountCanonicalForm). This option is not required but if it is not supplied, usernames in backslash form (e.g., FOO\alice) are not supported.
accountFilterFormat The LDAP search filter used to search for accounts. This string is a printf()-style expression that must contain one '%s' to accomodate the username. The default value is '(&(objectClass=user)(sAMAccountName=%s))', unless bindRequiresDn is set to TRUE, in which case the default is '(&(objectClass=posixAccount)(uid=%s))'. For example, if for some reason you wanted to use bindRequiresDn = true with AD you would need to set accountFilterFormat = '(&(objectClass=user)(sAMAccountName=%s))'.
optReferrals If set to TRUE, this option indicates to the LDAP client that referrals should be followed. The default value is FALSE.


If you enable useStartTls = TRUE or useSsl = TRUE you may find that the LDAP client generates an error claiming that it cannot validate the server's certificate. Assuming the PHP LDAP extension is ultimately linked to the OpenLDAP client libraries, to resolve this issue you can set "TLS_REQCERT never" in the OpenLDAP client ldap.conf (and restart the web server) to indicate to the OpenLDAP client library that you trust the server. Alternatively, if you are concerned that the server could be spoofed, you can export the LDAP server's root certificate and put it on the web server so that the OpenLDAP client can validate the server's identity.

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