LDAP

There are different ways to make RackTables recognize LDAP accounts instead of local accounts. One way is to configure RackTables to communicate with an LDAP server directly. In this case both password validity and group membership information are available inside RackTables. Group membership can be used in permission rules to implement site's access control policy. Another way is to configure RackTables to trust the authentication already performed by httpd, which in turn is configured to authenticate HTTP(S) clients in LDAP. This is sometimes the case, when the system administrator wants to reuse a working httpd+mod_auth_ldap setup. The drawback of this method is that group membership information wouldn't be available at RackTables level.

trusting httpd

$user_auth_src = 'httpd';
$require_local_account = FALSE;

direct access to LDAP

The following settings configure direct communication with LDAP server. Note that if your LDAP configuration doesn't work, you can revert to local passwords by setting $user_auth_src = 'database'.

$user_auth_src = 'ldap';
$require_local_account = FALSE;

The first setting makes RackTables execute the configuration defined in $LDAP_options. The second option makes RackTables accept any valid account existing in LDAP. Historically a user is required to be on the list of local accounts regardless of how his password is verified. For most LDAP enviroments this restriction makes no sense.

Further configuration is done through $LDAP_options array. Its content varies in each particular environment depending on the type of LDAP server software, its schema and configuration. RackTables has been reported to work with OpenLDAP, ActiveDirectory and eDirectory servers. Meaning of each LDAP option is explained below. The table is accurate as of RackTables release 0.19.5.

option(s)	is mandatory?	description
server	yes	Hostname or IP address of LDAP server(s). When multiple servers are listed (delimited with spaces), they are used in the order of appearance until a successful connection is made.
cache_refresh cache_retry cache_expiry	yes	LDAP cache parameters, values in seconds. Refresh, retry and expiry values are treated exactly as those for DNS SOA record. Example values 300-15-600 mean: unconditionally remeber successful auth for 5 minutes, after that still permit user access, but try to revalidate the password on the server (not more often, than once in 15 seconds). After 10 minutes of unsuccessful retries give up and deny access until the LDAP server gets fixed. Like in DNS, the following condition must be always met: cache_retry <= cache_refresh <= cache_expiry To disable LDAP cache completely, set cache_refresh, cache_retry and cache_expiry to 0.
domain	varies	When this option is set, it is used for "domain" authentication mode specific to ActiveDirectory. In this mode the plain username presented by a user is joined with the configured domain name and the resulting string ("username@example.com") is used for password validation. Either "domain" or "search" mode must be enabled.
search_attr search_dn	varies	These options enable "search" authentication mode, which is more common for OpenLDAP and eDirectory servers. It is assumed, that many nested organizational units (OUs) exist within within an organization (O). Traditional LDAP implementations let each OU have its own list of usernames, and some usernames remain unique only within their OU. The following approach is used to distinguish the users. Users with globally unique usernames present their plain username. Other users know, that they have to use their UID instead. A LDAP database is maintaned so, that UID is a little longer, than username, but yet unique. To map presented UID into common name (CN, which is the canonical, long form of user's identifier) LDAP search is performed. All this works automatically, once the search DN and search attribute are configured. Either "domain" or "search" mode must be enabled.
displayname_attrs	no	This list of space-delimited attributes is used to build the "displayed name" of a user, which is used to print a greeting message. This setting only works in "search" mode.
group_attr	no (has default)	Group membership attribute, default value is "memberof". When it is configured, it is used as the source of authenticated user's LDAP groups. Upon successful authentication the groups are mapped into a set of autotags in the form {$lgcn_LDAPGroup1}, {$lgcn_LDAPGroup2}, {$lgcn_LDAPGroup3}... This setting only works in "search" mode.
group_filter	no (has default)	User groups filter regexp (PCRE). The purpose of this filter is to decide, which LDAP groups are mapped to a {$lgcn_XXXXXX} autotag and which are not. Group DNs matching the regexp are mapped and the other groups are not. The default value is "/^[Cc][Nn]=([^,]+)/", which matches any valid LDAP group. In order to generate the autotags only for groups within a given OU, the following PCRE could be used: "/CN=([^,]+),OU=RackTables,OU=IT,O=company/"
options	no	List of LDAP protocol options as explained at http://php.net/manual/en/function.ldap-set-option.php PHP LDAP extension often uses LDAP protocol version 2 by default, which is deprecated. All examples below include a setting to use LDAP protocol version 3.

configuring for OpenLDAP in "search" mode

$LDAP_options = array
(
  'server' => 'ldap.example.com',
  'cache_refresh' => 300,
  'cache_retry' => 15,
  'cache_expiry' => 600,
  'search_attr' => 'uid',
  'search_dn' => 'OU=people,O=YourCompany',
  'displayname_attrs' => 'givenname familyname',
  'options' => array (LDAP_OPT_PROTOCOL_VERSION => 3),
);

configuring for eDirectory in "search" mode

$LDAP_options = array
(
  'server' => 'ldap.example.com',
  'cache_refresh' => 300,
  'cache_retry' => 15,
  'cache_expiry' => 600,
  'search_attr' => 'uid',
  'search_dn' => 'OU=people,O=YourCompany',
  'displayname_attrs' => 'givenname familyname',
  'group_attr' => 'groupmembership',
  'options' => array (LDAP_OPT_PROTOCOL_VERSION => 3),
);

configuring for ActiveDirectory in "domain" mode

Note the additional protocol option, which disables referrals to make LDAP search happen in the base DN, but not in nested OUs/CNs. This is important for some ActiveDirectory servers.

$LDAP_options = array
(
  'server' => 'domaincontroller.example.com',
  'cache_refresh' => 300,
  'cache_retry' => 15,
  'cache_expiry' => 600,
  'domain' => 'example.com',
  'search_attr' => 'sAMAccountName',
  'search_dn' => 'OU=Users,DC=example,DC=com',
  'displayname_attrs' => 'givenname sn',
  'options' => array (LDAP_OPT_PROTOCOL_VERSION => 3, LDAP_OPT_REFERRALS => 0),
);