8.4.1.12 Pluggable Authentication System Variables

These variables are unavailable unless the appropriate server-side plugin is installed:

• authentication_ldap_sasl for system variables with names of the form authentication_ldap_sasl_xxx

• authentication_ldap_simple for system variables with names of the form authentication_ldap_simple_xxx

Table 8.27 Authentication Plugin System Variable Summary

Name	Cmd-Line	Option File	System Var	Status Var	Var Scope	Dynamic
authentication_kerberos_service_key_tab	Yes	Yes	Yes		Global	No
authentication_kerberos_service_principal	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_auth_method_name	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_bind_base_dn	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_bind_root_dn	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_bind_root_pwd	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_ca_path	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_connect_timeout	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_group_search_attr	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_group_search_filter	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_init_pool_size	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_log_status	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_max_pool_size	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_referral	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_response_timeout	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_server_host	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_server_port	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_tls	Yes	Yes	Yes		Global	Yes
authentication_ldap_sasl_user_search_attr	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_auth_method_name	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_bind_base_dn	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_bind_root_dn	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_bind_root_pwd	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_ca_path	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_connect_timeout	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_group_search_attr	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_group_search_filter	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_init_pool_size	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_log_status	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_max_pool_size	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_referral	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_response_timeout	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_server_host	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_server_port	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_tls	Yes	Yes	Yes		Global	Yes
authentication_ldap_simple_user_search_attr	Yes	Yes	Yes		Global	Yes
authentication_policy	Yes	Yes	Yes		Global	Yes
authentication_webauthn_rp_id	Yes	Yes	Yes		Global	Yes
authentication_windows_log_level	Yes	Yes	Yes		Global	No
authentication_windows_use_principal_name	Yes	Yes	Yes		Global	No

• authentication_kerberos_service_key_tab

  Command-Line Format	--authentication-kerberos-service-key-tab=file_name
  System Variable	authentication_kerberos_service_key_tab
  Scope	Global
  Dynamic	No
  SET_VAR Hint Applies	No
  Type	File name
  Default Value	datadir/mysql.keytab

  The name of the server-side key-table (“keytab”) file containing Kerberos service keys to authenticate MySQL service tickets received from clients. The file name should be given as an absolute path name. If this variable is not set, the default is mysql.keytab in the data directory.

  The file must exist and contain a valid key for the service principal name (SPN) or authentication of clients will fail. (The SPN and same key also must be created in the Kerberos server.) The file may contain multiple service principal names and their respective key combinations.

  The file must be generated by the Kerberos server administrator and be copied to a location accessible by the MySQL server. The file can be validated to make sure that it is correct and was copied properly using this command:

  klist -k file_name

  For information about keytab files, see https://web.mit.edu/kerberos/krb5-latest/doc/basic/keytab_def.html.

• authentication_kerberos_service_principal

  Command-Line Format	--authentication-kerberos-service-principal=name
  System Variable	authentication_kerberos_service_principal
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	mysql/host_name@realm_name

  The Kerberos service principal name (SPN) that the MySQL server sends to clients.

  The value is composed from the service name (mysql), a host name, and a realm name. The default value is mysql/host_name@realm_name. The realm in the service principal name enables retrieving the exact service key.

  To use a nondefault value, set the value using the same format. For example, to use a host name of krbauth.example.com and a realm of MYSQL.LOCAL, set authentication_kerberos_service_principal to mysql/[e-mail].

  The service principal name and service key must already be present in the database managed by the KDC server.

  There can be service principal names that differ only by realm name.

• authentication_ldap_sasl_auth_method_name

  Command-Line Format	--authentication-ldap-sasl-auth-method-name=value
  System Variable	authentication_ldap_sasl_auth_method_name
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	SCRAM-SHA-1
  Valid Values	SCRAM-SHA-1 SCRAM-SHA-256 GSSAPI

  For SASL LDAP authentication, the authentication method name. Communication between the authentication plugin and the LDAP server occurs according to this authentication method to ensure password security.

  These authentication method values are permitted:

  • SCRAM-SHA-1: Use a SASL challenge-response mechanism.

    The client-side authentication_ldap_sasl_client plugin communicates with the SASL server, using the password to create a challenge and obtain a SASL request buffer, then passes this buffer to the server-side authentication_ldap_sasl plugin. The client-side and server-side SASL LDAP plugins use SASL messages for secure transmission of credentials within the LDAP protocol, to avoid sending the cleartext password between the MySQL client and server.

  • SCRAM-SHA-256: Use a SASL challenge-response mechanism.

    This method is similar to SCRAM-SHA-1, but is more secure. It requires an OpenLDAP server built using Cyrus SASL 2.1.27 or higher.

  • GSSAPI: Use Kerberos, a passwordless and ticket-based protocol.

    GSSAPI/Kerberos is supported as an authentication method for MySQL clients and servers only on Linux. It is useful in Linux environments where applications access LDAP using Microsoft Active Directory, which has Kerberos enabled by default.

    The client-side authentication_ldap_sasl_client plugin obtains a service ticket using the ticket-granting ticket (TGT) from Kerberos, but does not use LDAP services directly. The server-side authentication_ldap_sasl plugin routes Kerberos messages between the client-side plugin and the LDAP server. Using the credentials thus obtained, the server-side plugin then communicates with the LDAP server to interpret LDAP authentication messages and retrieve LDAP groups.

• authentication_ldap_sasl_bind_base_dn

  Command-Line Format	--authentication-ldap-sasl-bind-base-dn=value
  System Variable	authentication_ldap_sasl_bind_base_dn
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	NULL

  For SASL LDAP authentication, the base distinguished name (DN). This variable can be used to limit the scope of searches by anchoring them at a certain location (the “base”) within the search tree.

  Suppose that members of one set of LDAP user entries each have this form:

  uid=user_name,ou=People,dc=example,dc=com

  And that members of another set of LDAP user entries each have this form:

  uid=user_name,ou=Admin,dc=example,dc=com

  Then searches work like this for different base DN values:

  • If the base DN is ou=People,dc=example,dc=com: Searches find user entries only in the first set.

  • If the base DN is ou=Admin,dc=example,dc=com: Searches find user entries only in the second set.

  • If the base DN is ou=dc=example,dc=com: Searches find user entries in the first or second set.

  In general, more specific base DN values result in faster searches because they limit the search scope more.

• authentication_ldap_sasl_bind_root_dn

  Command-Line Format	--authentication-ldap-sasl-bind-root-dn=value
  System Variable	authentication_ldap_sasl_bind_root_dn
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	NULL

  For SASL LDAP authentication, the root distinguished name (DN). This variable is used in conjunction with authentication_ldap_sasl_bind_root_pwd as the credentials for authenticating to the LDAP server for the purpose of performing searches. Authentication uses either one or two LDAP bind operations, depending on whether the MySQL account names an LDAP user DN:

  • If the account does not name a user DN: authentication_ldap_sasl performs an initial LDAP binding using authentication_ldap_sasl_bind_root_dn and authentication_ldap_sasl_bind_root_pwd. (These are both empty by default, so if they are not set, the LDAP server must permit anonymous connections.) The resulting bind LDAP handle is used to search for the user DN, based on the client user name. authentication_ldap_sasl performs a second bind using the user DN and client-supplied password.

  • If the account does name a user DN: The first bind operation is unnecessary in this case. authentication_ldap_sasl performs a single bind using the user DN and client-supplied password. This is faster than if the MySQL account does not specify an LDAP user DN.

• authentication_ldap_sasl_bind_root_pwd

  Command-Line Format	--authentication-ldap-sasl-bind-root-pwd=value
  System Variable	authentication_ldap_sasl_bind_root_pwd
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	NULL

  For SASL LDAP authentication, the password for the root distinguished name. This variable is used in conjunction with authentication_ldap_sasl_bind_root_dn. See the description of that variable.

• authentication_ldap_sasl_ca_path

  Command-Line Format	--authentication-ldap-sasl-ca-path=value
  System Variable	authentication_ldap_sasl_ca_path
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	NULL

  For SASL LDAP authentication, the absolute path of the certificate authority file. Specify this file if it is desired that the authentication plugin perform verification of the LDAP server certificate.

  Note

  In addition to setting the authentication_ldap_sasl_ca_path variable to the file name, you must add the appropriate certificate authority certificates to the file and enable the authentication_ldap_sasl_tls system variable. These variables can be set to override the default OpenLDAP TLS configuration; see LDAP Pluggable Authentication and ldap.conf

• authentication_ldap_sasl_connect_timeout

  Command-Line Format	--authentication-ldap-sasl-connect-timeout=#
  System Variable	authentication_ldap_sasl_connect_timeout
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	30
  Minimum Value	0
  Maximum Value	31536000
  Unit	seconds

  Specifies the time (in seconds) that MySQL server waits to connect to the LDAP server using TCP.

  When a MySQL account authenticates using LDAP, MySQL server attempts to establish a TCP connection with the LDAP server, which it uses to send an LDAP bind request over the connection. If the LDAP server does not respond to TCP handshake after a configured amount of time, MySQL abandons the TCP handshake attempt and emits an error message. If the timeout setting is zero, MySQL server ignores this system variable setting. For more information, see Setting Timeouts for LDAP Pluggable Authentication.

  Note

  If you set this variable to a timeout value that is greater than the host system's default value, the shorter system timeout is used.

• authentication_ldap_sasl_group_search_attr

  Command-Line Format	--authentication-ldap-sasl-group-search-attr=value
  System Variable	authentication_ldap_sasl_group_search_attr
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	cn

  For SASL LDAP authentication, the name of the attribute that specifies group names in LDAP directory entries. If authentication_ldap_sasl_group_search_attr has its default value of cn, searches return the cn value as the group name. For example, if an LDAP entry with a uid value of user1 has a cn attribute of mygroup, searches for user1 return mygroup as the group name.

  This variable should be the empty string if you want no group or proxy authentication.

  If the group search attribute is isMemberOf, LDAP authentication directly retrieves the user attribute isMemberOf value and assigns it as group information. If the group search attribute is not isMemberOf, LDAP authentication searches for all groups where the user is a member. (The latter is the default behavior.) This behavior is based on how LDAP group information can be stored two ways: 1) A group entry can have an attribute named memberUid or member with a value that is a user name; 2) A user entry can have an attribute named isMemberOf with values that are group names.

• authentication_ldap_sasl_group_search_filter

  Command-Line Format	--authentication-ldap-sasl-group-search-filter=value
  System Variable	authentication_ldap_sasl_group_search_filter
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	(|(&(objectClass=posixGroup)(memberUid=%s))(&(objectClass=group)(member=%s)))

  For SASL LDAP authentication, the custom group search filter.

  The search filter value can contain {UA} and {UD} notation to represent the user name and the full user DN. For example, {UA} is replaced with a user name such as "admin", whereas {UD} is replaced with a use full DN such as "uid=admin,ou=People,dc=example,dc=com". The following value is the default, which supports both OpenLDAP and Active Directory:

  (|(&(objectClass=posixGroup)(memberUid={UA}))
    (&(objectClass=group)(member={UD})))

  In some cases for the user scenario, memberOf is a simple user attribute that holds no group information. For additional flexibility, an optional {GA} prefix can be used with the group search attribute. Any group attribute with a {GA} prefix is treated as a user attribute having group names. For example, with a value of {GA}MemberOf, if the group value is the DN, the first attribute value from the group DN is returned as the group name.

• authentication_ldap_sasl_init_pool_size

  Command-Line Format	--authentication-ldap-sasl-init-pool-size=#
  System Variable	authentication_ldap_sasl_init_pool_size
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	10
  Minimum Value	0
  Maximum Value	32767
  Unit	connections

  For SASL LDAP authentication, the initial size of the pool of connections to the LDAP server. Choose the value for this variable based on the average number of concurrent authentication requests to the LDAP server.

  The plugin uses authentication_ldap_sasl_init_pool_size and authentication_ldap_sasl_max_pool_size together for connection-pool management:

  • When the authentication plugin initializes, it creates authentication_ldap_sasl_init_pool_size connections, unless authentication_ldap_sasl_max_pool_size=0 to disable pooling.

  • If the plugin receives an authentication request when there are no free connections in the current connection pool, the plugin can create a new connection, up to the maximum connection pool size given by authentication_ldap_sasl_max_pool_size.

  • If the plugin receives a request when the pool size is already at its maximum and there are no free connections, authentication fails.

  • When the plugin unloads, it closes all pooled connections.

  Changes to plugin system variable settings may have no effect on connections already in the pool. For example, modifying the LDAP server host, port, or TLS settings does not affect existing connections. However, if the original variable values were invalid and the connection pool could not be initialized, the plugin attempts to reinitialize the pool for the next LDAP request. In this case, the new system variable values are used for the reinitialization attempt.

  If authentication_ldap_sasl_max_pool_size=0 to disable pooling, each LDAP connection opened by the plugin uses the values the system variables have at that time.

• authentication_ldap_sasl_log_status

  Command-Line Format	--authentication-ldap-sasl-log-status=#
  System Variable	authentication_ldap_sasl_log_status
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	1
  Minimum Value	1
  Maximum Value	6

  For SASL LDAP authentication, the logging level for messages written to the error log. The following table shows the permitted level values and their meanings.

  Table 8.28 Log Levels for authentication_ldap_sasl_log_status

  Option Value	Types of Messages Logged
  1	No messages
  2	Error messages
  3	Error and warning messages
  4	Error, warning, and information messages
  5	Same as previous level plus debugging messages from MySQL
  6	Same as previous level plus debugging messages from LDAP library

  
  

  On the client side, messages can be logged to the standard output by setting the AUTHENTICATION_LDAP_CLIENT_LOG environment variable. The permitted and default values are the same as for authentication_ldap_sasl_log_status.

  The AUTHENTICATION_LDAP_CLIENT_LOG environment variable applies only to SASL LDAP authentication. It has no effect for simple LDAP authentication because the client plugin in that case is mysql_clear_password, which knows nothing about LDAP operations.

• authentication_ldap_sasl_max_pool_size

  Command-Line Format	--authentication-ldap-sasl-max-pool-size=#
  System Variable	authentication_ldap_sasl_max_pool_size
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	1000
  Minimum Value	0
  Maximum Value	32767
  Unit	connections

  For SASL LDAP authentication, the maximum size of the pool of connections to the LDAP server. To disable connection pooling, set this variable to 0.

  This variable is used in conjunction with authentication_ldap_sasl_init_pool_size. See the description of that variable.

• authentication_ldap_sasl_referral

  Command-Line Format	--authentication-ldap-sasl-referral[={OFF|ON}]
  System Variable	authentication_ldap_sasl_referral
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Boolean
  Default Value	OFF

  For SASL LDAP authentication, whether to enable LDAP search referral. See LDAP Search Referral.

  This variable can be set to override the default OpenLDAP referral configuration; see LDAP Pluggable Authentication and ldap.conf

• authentication_ldap_sasl_response_timeout

  Command-Line Format	--authentication-ldap-sasl-response-timeout=#
  System Variable	authentication_ldap_sasl_response_timeout
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	30
  Minimum Value	0
  Maximum Value	31536000
  Unit	seconds

  Specifies the time (in seconds) that MySQL server waits for the LDAP server to response to an LDAP bind request.

  When a MySQL account authenticates using LDAP, MySQL server sends an LDAP bind request to the LDAP server. If the LDAP server does not respond to the request after a configured amount of time, MySQL abandons the request and emits an error message. If the timeout setting is zero, MySQL server ignores this system variable setting. For more information, see Setting Timeouts for LDAP Pluggable Authentication.

• authentication_ldap_sasl_server_host

  Command-Line Format	--authentication-ldap-sasl-server-host=host_name
  System Variable	authentication_ldap_sasl_server_host
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String

  For SASL LDAP authentication, the LDAP server host. The permitted values for this variable depend on the authentication method:

  • For authentication_ldap_sasl_auth_method_name=SCRAM-SHA-1: The LDAP server host can be a host name or IP address.

  • For authentication_ldap_sasl_auth_method_name=SCRAM-SHA-256: The LDAP server host can be a host name or IP address.

• authentication_ldap_sasl_server_port

  Command-Line Format	--authentication-ldap-sasl-server-port=port_num
  System Variable	authentication_ldap_sasl_server_port
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	389
  Minimum Value	1
  Maximum Value	32376

  For SASL LDAP authentication, the LDAP server TCP/IP port number.

  If the LDAP port number is configured as 636 or 3269, the plugin uses LDAPS (LDAP over SSL) instead of LDAP. (LDAPS differs from startTLS.)

• authentication_ldap_sasl_tls

  Command-Line Format	--authentication-ldap-sasl-tls[={OFF|ON}]
  System Variable	authentication_ldap_sasl_tls
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Boolean
  Default Value	OFF

  For SASL LDAP authentication, whether connections by the plugin to the LDAP server are secure. If this variable is enabled, the plugin uses TLS to connect securely to the LDAP server. This variable can be set to override the default OpenLDAP TLS configuration; see LDAP Pluggable Authentication and ldap.conf If you enable this variable, you may also wish to set the authentication_ldap_sasl_ca_path variable.

  MySQL LDAP plugins support the StartTLS method, which initializes TLS on top of a plain LDAP connection.

  LDAPS can be used by setting the authentication_ldap_sasl_server_port system variable.

• authentication_ldap_sasl_user_search_attr

  Command-Line Format	--authentication-ldap-sasl-user-search-attr=value
  System Variable	authentication_ldap_sasl_user_search_attr
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	uid

  For SASL LDAP authentication, the name of the attribute that specifies user names in LDAP directory entries. If a user distinguished name is not provided, the authentication plugin searches for the name using this attribute. For example, if the authentication_ldap_sasl_user_search_attr value is uid, a search for the user name user1 finds entries with a uid value of user1.

• authentication_ldap_simple_auth_method_name

  Command-Line Format	--authentication-ldap-simple-auth-method-name=value
  System Variable	authentication_ldap_simple_auth_method_name
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	SIMPLE
  Valid Values	SIMPLE AD-FOREST

  For simple LDAP authentication, the authentication method name. Communication between the authentication plugin and the LDAP server occurs according to this authentication method.

  Note

  For all simple LDAP authentication methods, it is recommended to also set TLS parameters to require that communication with the LDAP server take place over secure connections.

  These authentication method values are permitted:

  • SIMPLE: Use simple LDAP authentication. This method uses either one or two LDAP bind operations, depending on whether the MySQL account names an LDAP user distinguished name. See the description of authentication_ldap_simple_bind_root_dn.

  • AD-FOREST: A variation on SIMPLE, such that authentication searches all domains in the Active Directory forest, performing an LDAP bind to each Active Directory domain until the user is found in some domain.

• authentication_ldap_simple_bind_base_dn

  Command-Line Format	--authentication-ldap-simple-bind-base-dn=value
  System Variable	authentication_ldap_simple_bind_base_dn
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	NULL

  For simple LDAP authentication, the base distinguished name (DN). This variable can be used to limit the scope of searches by anchoring them at a certain location (the “base”) within the search tree.

  Suppose that members of one set of LDAP user entries each have this form:

  uid=user_name,ou=People,dc=example,dc=com

  And that members of another set of LDAP user entries each have this form:

  uid=user_name,ou=Admin,dc=example,dc=com

  Then searches work like this for different base DN values:

  • If the base DN is ou=People,dc=example,dc=com: Searches find user entries only in the first set.

  • If the base DN is ou=Admin,dc=example,dc=com: Searches find user entries only in the second set.

  • If the base DN is ou=dc=example,dc=com: Searches find user entries in the first or second set.

  In general, more specific base DN values result in faster searches because they limit the search scope more.

• authentication_ldap_simple_bind_root_dn

  Command-Line Format	--authentication-ldap-simple-bind-root-dn=value
  System Variable	authentication_ldap_simple_bind_root_dn
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	NULL

  For simple LDAP authentication, the root distinguished name (DN). This variable is used in conjunction with authentication_ldap_simple_bind_root_pwd as the credentials for authenticating to the LDAP server for the purpose of performing searches. Authentication uses either one or two LDAP bind operations, depending on whether the MySQL account names an LDAP user DN:

  • If the account does not name a user DN: authentication_ldap_simple performs an initial LDAP binding using authentication_ldap_simple_bind_root_dn and authentication_ldap_simple_bind_root_pwd. (These are both empty by default, so if they are not set, the LDAP server must permit anonymous connections.) The resulting bind LDAP handle is used to search for the user DN, based on the client user name. authentication_ldap_simple performs a second bind using the user DN and client-supplied password.

  • If the account does name a user DN: The first bind operation is unnecessary in this case. authentication_ldap_simple performs a single bind using the user DN and client-supplied password. This is faster than if the MySQL account does not specify an LDAP user DN.

• authentication_ldap_simple_bind_root_pwd

  Command-Line Format	--authentication-ldap-simple-bind-root-pwd=value
  System Variable	authentication_ldap_simple_bind_root_pwd
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	NULL

  For simple LDAP authentication, the password for the root distinguished name. This variable is used in conjunction with authentication_ldap_simple_bind_root_dn. See the description of that variable.

• authentication_ldap_simple_ca_path

  Command-Line Format	--authentication-ldap-simple-ca-path=value
  System Variable	authentication_ldap_simple_ca_path
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	NULL

  For simple LDAP authentication, the absolute path of the certificate authority file. Specify this file if it is desired that the authentication plugin perform verification of the LDAP server certificate.

  Note

  In addition to setting the authentication_ldap_simple_ca_path variable to the file name, you must add the appropriate certificate authority certificates to the file and enable the authentication_ldap_simple_tls system variable. These variables can be set to override the default OpenLDAP TLS configuration; see LDAP Pluggable Authentication and ldap.conf

• authentication_ldap_simple_connect_timeout

  Command-Line Format	--authentication-ldap-simple-connect-timeout=#
  System Variable	authentication_ldap_simple_connect_timeout
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	30
  Minimum Value	0
  Maximum Value	31536000
  Unit	seconds

  Specifies the time (in seconds) that MySQL server waits to connect to the LDAP server using TCP.

  When a MySQL account authenticates using LDAP, MySQL server attempts to establish a TCP connection with the LDAP server, which it uses to send an LDAP bind request over the connection. If the LDAP server does not respond to TCP handshake after a configured amount of time, MySQL abandons the TCP handshake attempt and emits an error message. If the timeout setting is zero, MySQL server ignores this system variable setting. For more information, see Setting Timeouts for LDAP Pluggable Authentication.

  Note

  If you set this variable to a timeout value that is greater than the host system's default value, the shorter system timeout is used.

• authentication_ldap_simple_group_search_attr

  Command-Line Format	--authentication-ldap-simple-group-search-attr=value
  System Variable	authentication_ldap_simple_group_search_attr
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	cn

  For simple LDAP authentication, the name of the attribute that specifies group names in LDAP directory entries. If authentication_ldap_simple_group_search_attr has its default value of cn, searches return the cn value as the group name. For example, if an LDAP entry with a uid value of user1 has a cn attribute of mygroup, searches for user1 return mygroup as the group name.

  If the group search attribute is isMemberOf, LDAP authentication directly retrieves the user attribute isMemberOf value and assigns it as group information. If the group search attribute is not isMemberOf, LDAP authentication searches for all groups where the user is a member. (The latter is the default behavior.) This behavior is based on how LDAP group information can be stored two ways: 1) A group entry can have an attribute named memberUid or member with a value that is a user name; 2) A user entry can have an attribute named isMemberOf with values that are group names.

• authentication_ldap_simple_group_search_filter

  Command-Line Format	--authentication-ldap-simple-group-search-filter=value
  System Variable	authentication_ldap_simple_group_search_filter
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	(|(&(objectClass=posixGroup)(memberUid=%s))(&(objectClass=group)(member=%s)))

  For simple LDAP authentication, the custom group search filter.

  The search filter value can contain {UA} and {UD} notation to represent the user name and the full user DN. For example, {UA} is replaced with a user name such as "admin", whereas {UD} is replaced with a use full DN such as "uid=admin,ou=People,dc=example,dc=com". The following value is the default, which supports both OpenLDAP and Active Directory:

  (|(&(objectClass=posixGroup)(memberUid={UA}))
    (&(objectClass=group)(member={UD})))

  In some cases for the user scenario, memberOf is a simple user attribute that holds no group information. For additional flexibility, an optional {GA} prefix can be used with the group search attribute. Any group attribute with a {GA} prefix is treated as a user attribute having group names. For example, with a value of {GA}MemberOf, if the group value is the DN, the first attribute value from the group DN is returned as the group name.

• authentication_ldap_simple_init_pool_size

  Command-Line Format	--authentication-ldap-simple-init-pool-size=#
  System Variable	authentication_ldap_simple_init_pool_size
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	10
  Minimum Value	0
  Maximum Value	32767
  Unit	connections

  For simple LDAP authentication, the initial size of the pool of connections to the LDAP server. Choose the value for this variable based on the average number of concurrent authentication requests to the LDAP server.

  The plugin uses authentication_ldap_simple_init_pool_size and authentication_ldap_simple_max_pool_size together for connection-pool management:

  • When the authentication plugin initializes, it creates authentication_ldap_simple_init_pool_size connections, unless authentication_ldap_simple_max_pool_size=0 to disable pooling.

  • If the plugin receives an authentication request when there are no free connections in the current connection pool, the plugin can create a new connection, up to the maximum connection pool size given by authentication_ldap_simple_max_pool_size.

  • If the plugin receives a request when the pool size is already at its maximum and there are no free connections, authentication fails.

  • When the plugin unloads, it closes all pooled connections.

  Changes to plugin system variable settings may have no effect on connections already in the pool. For example, modifying the LDAP server host, port, or TLS settings does not affect existing connections. However, if the original variable values were invalid and the connection pool could not be initialized, the plugin attempts to reinitialize the pool for the next LDAP request. In this case, the new system variable values are used for the reinitialization attempt.

  If authentication_ldap_simple_max_pool_size=0 to disable pooling, each LDAP connection opened by the plugin uses the values the system variables have at that time.

• authentication_ldap_simple_log_status

  Command-Line Format	--authentication-ldap-simple-log-status=#
  System Variable	authentication_ldap_simple_log_status
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	1
  Minimum Value	1
  Maximum Value	6

  For simple LDAP authentication, the logging level for messages written to the error log. The following table shows the permitted level values and their meanings.

  Table 8.29 Log Levels for authentication_ldap_simple_log_status

  Option Value	Types of Messages Logged
  1	No messages
  2	Error messages
  3	Error and warning messages
  4	Error, warning, and information messages
  5	Same as previous level plus debugging messages from MySQL
  6	Same as previous level plus debugging messages from LDAP library

  
  

• authentication_ldap_simple_max_pool_size

  Command-Line Format	--authentication-ldap-simple-max-pool-size=#
  System Variable	authentication_ldap_simple_max_pool_size
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	1000
  Minimum Value	0
  Maximum Value	32767
  Unit	connections

  For simple LDAP authentication, the maximum size of the pool of connections to the LDAP server. To disable connection pooling, set this variable to 0.

  This variable is used in conjunction with authentication_ldap_simple_init_pool_size. See the description of that variable.

• authentication_ldap_simple_referral

  Command-Line Format	--authentication-ldap-simple-referral[={OFF|ON}]
  System Variable	authentication_ldap_simple_referral
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Boolean
  Default Value	OFF

  For simple LDAP authentication, whether to enable LDAP search referral. See LDAP Search Referral.

• authentication_ldap_simple_response_timeout

  Command-Line Format	--authentication-ldap-simple-response-timeout=#
  System Variable	authentication_ldap_simple_response_timeout
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	30
  Minimum Value	0
  Maximum Value	31536000
  Unit	seconds

  Specifies the time (in seconds) that MySQL server waits for the LDAP server to response to an LDAP bind request.

  When a MySQL account authenticates using LDAP, MySQL server sends an LDAP bind request to the LDAP server. If the LDAP server does not respond to the request after a configured amount of time, MySQL abandons the request and emits an error message. If the timeout setting is zero, MySQL server ignores this system variable setting. For more information, see Setting Timeouts for LDAP Pluggable Authentication.

• authentication_ldap_simple_server_host

  Command-Line Format	--authentication-ldap-simple-server-host=host_name
  System Variable	authentication_ldap_simple_server_host
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String

  For simple LDAP authentication, the LDAP server host. The permitted values for this variable depend on the authentication method:

  • For authentication_ldap_simple_auth_method_name=SIMPLE: The LDAP server host can be a host name or IP address.

  • For authentication_ldap_simple_auth_method_name=AD-FOREST. The LDAP server host can be an Active Directory domain name. For example, for an LDAP server URL of ldap://example.mem.local:389, the domain name can be mem.local.

    An Active Directory forest setup can have multiple domains (LDAP server IPs), which can be discovered using DNS. On Unix and Unix-like systems, some additional setup may be required to configure your DNS server with SRV records that specify the LDAP servers for the Active Directory domain. For information about DNS SRV, see RFC 2782.

    Suppose that your configuration has these properties:

    • The name server that provides information about Active Directory domains has IP address 10.172.166.100.

    • The LDAP servers have names ldap1.mem.local through ldap3.mem.local and IP addresses 10.172.166.101 through 10.172.166.103.

    You want the LDAP servers to be discoverable using SRV searches. For example, at the command line, a command like this should list the LDAP servers:

    host -t SRV _ldap._tcp.mem.local

    Perform the DNS configuration as follows:

    1. Add a line to /etc/resolv.conf to specify the name server that provides information about Active Directory domains:

       nameserver 10.172.166.100

    2. Configure the appropriate zone file for the name server with SRV records for the LDAP servers:

       _ldap._tcp.mem.local. 86400 IN SRV 0 100 389 ldap1.mem.local.
       _ldap._tcp.mem.local. 86400 IN SRV 0 100 389 ldap2.mem.local.
       _ldap._tcp.mem.local. 86400 IN SRV 0 100 389 ldap3.mem.local.

    3. It may also be necessary to specify the IP address for the LDAP servers in /etc/hosts if the server host cannot be resolved. For example, add lines like this to the file:

       10.172.166.101 ldap1.mem.local
       10.172.166.102 ldap2.mem.local
       10.172.166.103 ldap3.mem.local

    With the DNS configured as just described, the server-side LDAP plugin can discover the LDAP servers and tries to authenticate in all domains until authentication succeeds or there are no more servers.

    Windows needs no such settings as just described. Given the LDAP server host in the authentication_ldap_simple_server_host value, the Windows LDAP library searches all domains and attempts to authenticate.

• authentication_ldap_simple_server_port

  Command-Line Format	--authentication-ldap-simple-server-port=port_num
  System Variable	authentication_ldap_simple_server_port
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Integer
  Default Value	389
  Minimum Value	1
  Maximum Value	32376

  For simple LDAP authentication, the LDAP server TCP/IP port number.

  If the LDAP port number is configured as 636 or 3269, the plugin uses LDAPS (LDAP over SSL) instead of LDAP. (LDAPS differs from startTLS.)

• authentication_ldap_simple_tls

  Command-Line Format	--authentication-ldap-simple-tls[={OFF|ON}]
  System Variable	authentication_ldap_simple_tls
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	Boolean
  Default Value	OFF

  For simple LDAP authentication, whether connections by the plugin to the LDAP server are secure. If this variable is enabled, the plugin uses TLS to connect securely to the LDAP server. This variable can be set to override the default OpenLDAP TLS configuration; see LDAP Pluggable Authentication and ldap.conf If you enable this variable, you may also wish to set the authentication_ldap_simple_ca_path variable.

  MySQL LDAP plugins support the StartTLS method, which initializes TLS on top of a plain LDAP connection.

  LDAPS can be used by setting the authentication_ldap_simple_server_port system variable.

• authentication_ldap_simple_user_search_attr

  Command-Line Format	--authentication-ldap-simple-user-search-attr=value
  System Variable	authentication_ldap_simple_user_search_attr
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String
  Default Value	uid

  For simple LDAP authentication, the name of the attribute that specifies user names in LDAP directory entries. If a user distinguished name is not provided, the authentication plugin searches for the name using this attribute. For example, if the authentication_ldap_simple_user_search_attr value is uid, a search for the user name user1 finds entries with a uid value of user1.

• authentication_webauthn_rp_id

  Command-Line Format	--authentication-webauthn-rp-id=value
  System Variable	authentication_webauthn_rp_id
  Scope	Global
  Dynamic	Yes
  SET_VAR Hint Applies	No
  Type	String

  This variable specifies the relying party ID used for server-side plugin installation, device registration, and WebAuthn authentication. If WebAuthn authentication is attempted and this value is not the one expected by the device, the device assumes that it is not talking to the correct server and an error occurs. The maximum value length is 255 characters.