30.4. Creating Domains
ldap.otherexample.comdomain. SSSD allows requests using fully-qualified domain names, so requesting information for
firstname.lastname@example.org the proper user account. Specifying only the username returns the user for whichever domain comes first in the lookup order.
filter_usersoption, which excludes the specified users from being returned in a search.
Table 30.3. Identity Store and Authentication Type Combinations
|Identification Provider||Authentication Provider|
30.4.1. General Rules and Options for Configuring a Domain
domains = LOCAL,Name [domain/Name] id_provider = type auth_provider = type provider_specific = value global = value
Table 30.4. General [domain] Configuration Parameters
|id_provider||string|| Specifies the data provider identity backend to use for this domain. The supported identity backends are:
|auth_provider||string|| Sets the authentication provider used for the domain. The default value for this option is the value of |
|min_id,max_id||integer|| Optional. Specifies the UID and GID range for the domain. If a domain contains entries that are outside that range, they are ignored. The default value for |
|enumerate||Boolean|| Optional. Specifies whether to list the users and groups of a domain. Enumeration means that the entire set of available users and groups on the remote source is cached on the local machine. When enumeration is disabled, users and groups are only cached as they are requested.
The default value for this parameter is
When enumeration is enabled, reinitializing a client results in a complete refresh of the entire set of available users and groups from the remote source. Similarly, when SSSD is connected to a new server, the entire set of available users and groups from the remote source is pulled and cached on the local machine. In a domain with a large number of clients connected to a remote source, this refresh process can harm the network performance because of frequent queries from the clients. If the set of available users and groups is large enough, it degrades client performance as well.
|cache_credentials||Boolean|| Optional. Specifies whether to store user credentials in the local SSSD domain database cache. The default value for this parameter is |
|entry_cache_timeout||integer||Optional. Specifies how long, in seconds, SSSD should cache positive cache hits. A positive cache hit is a successful query.|
|use_fully_qualified_names||Boolean|| Optional. Specifies whether requests to this domain require fully-qualified domain names. If set to |
SSSD can only parse names based on the domain name, not the realm name. The same name can be used for both domains and realms, however.
30.4.2. Configuring an LDAP Domain
- Red Hat Directory Server
- Microsoft Active Directory 2008, with Subsystem for UNIX-based Applications
184.108.40.206. Parameters for Configuring an LDAP Domain
Table 30.5. LDAP Domain Configuration Parameters
|ldap_uri||Gives a comma-separated list of the URIs of the LDAP servers to which SSSD will connect. The list is given in order of preference, so the first server in the list is tried first. Listing additional servers provides failover protection. This can be detected from the DNS SRV records if it is not given.|
|ldap_search_base||Gives the base DN to use for performing LDAP user operations.|
|ldap_tls_reqcert|| Specifies how to check for SSL server certificates in a TLS session. There are four options:
The default is hard.
|ldap_tls_cacert|| Gives the full path and file name to the file that contains the CA certificates for all of the CAs that SSSD recognizes. SSSD will accept any certificate issued by these CAs.
This uses the OpenLDAP system defaults if it is not given explicitly.
|ldap_referrals|| Sets whether SSSD will use LDAP referrals, meaning forwarding queries from one LDAP database to another. SSSD supports database-level and subtree referrals. For referrals within the same LDAP server, SSSD will adjust the DN of the entry being queried. For referrals that go to different LDAP servers, SSSD does an exact match on the DN. Setting this value to |
|ldap_schema|| Sets what version of schema to use when searching for user entries. This can be either |
In RFC 2307, group objects use a multi-valued attribute,
For example, with RFC 2307bis, all groups are returned when using nested groups or primary/secondary groups.
$ id uid=500(myserver) gid=500(myserver) groups=500(myserver),510(myothergroup)
If SSSD is using RFC 2307 schema, only the primary group is returned.
This setting only affects how SSSD determines the group members. It does not change the actual user data.
|ldap_search_timeout|| Sets the time, in seconds, that LDAP searches are allowed to run before they are canceled and cached results are returned. This defaults to five when the |
When an LDAP search times out, SSSD automatically switches to offline mode.
|ldap_network_timeout||Sets the time, in seconds, SSSD attempts to poll an LDAP server after a connection attempt fails. The default is six seconds.|
|ldap_opt_timeout||Sets the time, in seconds, to wait before aborting synchronous LDAP operations if no response is received from the server. This option also controls the timeout when communicating with the KDC in case of a SASL bind. The default is five seconds.|
220.127.116.11. LDAP Domain Example
sssd.conffile. For example:
domains = LOCAL,LDAP1,AD,PROXYNIS
Example 30.1. A Basic LDAP Domain Configuration
- An LDAP server
- The search base
- A way to establish a secure connection
# An LDAP domain [domain/LDAP] enumerate = false cache_credentials = true id_provider = ldap auth_provider = ldap ldap_uri = ldaps://ldap.example.com:636 ldap_search_base = dc=example,dc=com
ldap_id_use_start_tlsoption to use Start TLS and then
ldap_tls_cacertto identify the CA certificate which issued the SSL server certificates.
# An LDAP domain [domain/LDAP] enumerate = false cache_credentials = true id_provider = ldap auth_provider = ldap ldap_uri = ldap://ldap.example.com ldap_search_base = dc=example,dc=com ldap_id_use_start_tls = true ldap_tls_reqcert = demand ldap_tls_cacert = /etc/pki/tls/certs/ca-bundle.crt
18.104.22.168. Active Directory Domain Example
authconfig, set the Linux client to use Active Directory as its LDAP identity provider. For example:
authconfig --enableldap --enableldapauth --ldapserver=ldap://ad.example.com:389 --enablekrb5 --krb5realm AD-REALM.EXAMPLE.COM --krb5kdc ad-kdc.example.com:88 --krb5adminserver ad-kdc.example.com:749 --updateThe
authconfigcommand is described in Section 29.4, “Command Line Version”.
- Create the Active Directory Domain Services role.
- Add the Identity Management for UNIX service to the Active Directory Domain Services role. Use the Unix NIS domain as the domain name in the configuration.
- On the Active Directory server, create a new Computer object with the name of the Linux client.
- In the Administrative Tools menu, select the Active Directory Users and Computers application.
- Expand the Active Directory root object, such as
- Right-click Computers, and select the and the item.
- Enter the name for the Linux client, such as
rhel-server, and click .
- Expand the Computers object.
- Right-click the
rhel-serverobject, and select .
- In the UNIX Attributes, enter the name of the Linux NIS domain and the IP address of the Linux server.Click.
- From the command prompt on the Active Directory server, create a machine account, password, and UPN for the Linux host principal.
C:\> setspn -A host/rhel-server.example.com@AD-REALM.EXAMPLE.COM rhel-server Registering ServicePrincipalNames for CN=rhel server,CN=Computers,DC=ad,DC=example,DC=com host/rhel server.example.com@AD-REALM.EXAMPLE.COM Updated object C:\> setspn -L rhel-server Registered ServicePrincipalNames for CN=rhel server,CN=Computers,DC=ad,DC=example,DC=com: host/rhel server.example.com@AD-REALM.EXAMPLE.COM C:\> ktpass /princ host/rhel-server.example.com@AD-REALM.EXAMPLE.COM /out rhel-server.keytab /crypto all /ptype KRB5_NT_PRINCIPAL -desonly /mapuser AD\rhel-server$ +rndPass Targeting domain controller: ad.example.com Using legacy password setting method Successfully mapped host/rhel server.redhat.com ... 8< ...
- Copy the keytab from the Active Directory server to the Linux client, and save it as
- On the Linux system, reset the permissions and owner for the keytab file.
[root@rhel-server ~]# chown root:root /etc/krb5.keytab [root@rhel-server ~]# chmod 0600 /etc/krb5.keytab
- Restore the SELinux file permissions for the keytab.
[root@rhel-server ~]# restorecon /etc/krb5.keytab
- Verify that the host can connect to the Active Directory domain.
[root@rhel-server ~]# kinit -k -t /etc/krb5.keytab host/rhel-server.example.com@AD-REALM.EXAMPLE.COM
- On the Active Directory server, create a a group for the Linux users.
- Create a new group named unixusers.
- Open the unixusers group and open the Unix Attributes tab.
- Configure the Unix settings:
- The NIS domain
- The UID
- The login shell, to
- The home directory, to
- The primary group name, to
- Then, configure the SSSD domain on the Linux machine.
Example 30.2. An Active Directory 2008 Domain
[root@rhel-server ~]# vim /etc/sssd/sssd.conf [sssd] config_file_version = 2 domains = ad.example.com services = nss, pam [nss] [pam] [domain/ad.example.com] cache_credentials = true enumerate = false id_provider = ldap auth_provider = krb5 chpass_provider = krb5 access_provider = ldap ldap_sasl_mech = GSSAPI ldap_sasl_authid = host/rhel-server.example.com@AD-REALM.EXAMPLE.COM ldap_schema = rfc2307bis ldap_user_search_base = ou=user accounts,dc=ad,dc=example,dc=com ldap_user_object_class = user ldap_user_home_directory = unixHomeDirectory ldap_user_principal = userPrincipalName ldap_user_name = sAMAccountName ldap_group_search_base = ou=groups,dc=ad,dc=example,dc=com ldap_group_object_class = group ldap_access_order = expire ldap_account_expire_policy = ad ldap_force_upper_case_realm = true ldap_disable_referrals = true #krb5_server = server.ad.example.com krb5_realm = AD-REALM.EXAMPLE.COMThese options are described in the man page for LDAP domain configuration,
- Restart SSSD.
[root@rhel-server ~]# service sssd restart
22.214.171.124. Using IP Addresses in Certificate Subject Names
ldap_urioption instead of the server name may cause the TLS/SSL connection to fail. TLS/SSL certificates contain the server name, not the IP address. However, the subject alternative name field in the certificate can be used to include the IP address of the server, which allows a successful secure connection using an IP address.
- Convert an existing certificate into a certificate request. The signing key (
-signkey) is the key of the issuer of whatever CA originally issued the certificate. If this is done by an external CA, it requires a separate PEM file; if the certificate is self-signed, then this is the certificate itself. For example:
openssl x509 -x509toreq -in old_cert.pem -out req.pem -signkey key.pemWith a self-signed certificate:
openssl x509 -x509toreq -in old_cert.pem -out req.pem -signkey old_cert.pem
- Edit the
/etc/pki/tls/openssl.cnfconfiguration file to include the server's IP address under the
[ v3_ca ]section:
subjectAltName = IP:10.0.0.10
- Use the generated certificate request to generate a new self-signed certificate with the specified IP address:
openssl x509 -req -in req.pem -out new_cert.pem -extfile ./openssl.cnf -extensions v3_ca -signkey old_cert.pemThe
-extensionsoption sets which extensions to use with the certificate. For this, it should be v3_ca to load the appropriate section.
- Copy the private key block from the
old_cert.pemfile into the
new_cert.pemfile to keep all relevant information in one file.
30.4.3. Configuring Kerberos Authentication with a Domain
krb5_kpasswdoption to specify where the password changing service is running or if it is running on a non-default port. If the
krb5_kpasswdoption is not defined, SSSD tries to use the Kerberos KDC to change the password.
sssd-krb5(5)man page has more information about Kerberos configuration options.
Example 30.3. Basic Kerberos Authentication
# A domain with identities provided by LDAP and authentication by Kerberos [domain/KRBDOMAIN] enumerate = false id_provider = ldap chpass_provider = krb5 ldap_uri = ldap://ldap.example.com ldap_search_base = dc=example,dc=com ldap-tls_reqcert = demand ldap_tls_cacert = /etc/pki/tls/certs/ca-bundle.crt auth_provider = krb5 krb5_server = 192.168.1.1, kerberos.example.com krb5_realm = EXAMPLE.COM krb5_kpasswd = kerberos.admin.example.com krb5_auth_timeout = 15
Table 30.6. Kerberos Authentication Configuration Parameters
|chpass_provider||Specifies which service to use for password change operations. This is assumed to be the same as the authentication provider. To use Kerberos, set this to krb5.|
|krb5_server|| Gives a comma-separated list of IP addresses or hostnames of Kerberos servers to which SSSD will connect. The list is given in order of preference, so the first server in the list is tried first. Listing additional servers provides failover protection.
When using service discovery for KDC or kpasswd servers, SSSD first searches for DNS entries that specify UDP as the connection protocol, and then falls back to TCP.
|krb5_realm||Identifies the Kerberos realm served by the KDC.|
|krb5_lifetime||Requests a Kerberos ticket with the specified lifetime in seconds (s), minutes (m), hours (h) or days (d).|
|krb5_renewable_lifetime||Requests a renewable Kerberos ticket with a total lifetime that is specified in seconds (s), minutes (m), hours (h) or days (d).|
|krb5_renew_interval||Sets the time, in seconds, for SSSD to check if tickets should be renewed. Tickets are renewed automatically once they exceed half their lifetime. If this option is missing or set to zero, then automatic ticket renewal is disabled.|
|krb5_store_password_if_offline|| Sets whether to store user passwords if the Kerberos authentication provider is offline, and then to use that cache to request tickets when the provider is back online. The default is |
|krb5_kpasswd||Lists alternate Kerberos kadmin servers to use if the change password service is not running on the KDC.|
|krb5_ccname_template|| Gives the directory to use to store the user's credential cache. This can be templatized, and the following tokens are supported:
krb5_ccname_template = FILE:%d/krb5cc_%U_XXXXXX
|krb5_ccachedir|| Specifies the directory to store credential caches. This can be templatized, using the same tokens as |
|krb5_auth_timeout||Gives the time, in seconds, before an online authentication or change password request is aborted. If possible, the authentication request is continued offline. The default is 15 seconds.|
30.4.4. Configuring a Proxy Domain
Table 30.7. Proxy Domain Configuration Parameters
|proxy_pam_target|| Specifies the target to which PAM must proxy as an authentication provider. The PAM target is a file containing PAM stack information in the default PAM directory, |
This is used to proxy an authentication provider.
Ensure that the proxy PAM stack does not recursively include
|proxy_lib_name|| Specifies which existing NSS library to proxy identity requests through.
This is used to proxy an identity provider.
Example 30.4. Proxy Identity and Kerberos Authentication
proxy_lib_nameparameter. This library can be anything as long as it is compatible with the given authentication service. For a Kerberos authentication provider, it must be a Kerberos-compatible library, like NIS.
[domain/PROXY_KRB5] auth_provider = krb5 krb5_server = 192.168.1.1 krb5_realm = EXAMPLE.COM id_provider = proxy proxy_lib_name = nis enumerate = true cache_credentials = true
Example 30.5. LDAP Identity and Proxy Authentication
proxy_pam_targetparameter. This library must be a PAM module that is compatible with the given identity provider. For example, this uses a PAM fingerprint module with LDAP:
[domain/LDAP_PROXY] id_provider = ldap ldap_uri = ldap://example.com ldap_search_base = dc=example,dc=com auth_provider = proxy proxy_pam_target = sssdpamproxy enumerate = true cache_credentials = true
sssdpamproxy, so create a
/etc/pam.d/sssdpamproxyfile and load the PAM/LDAP modules:
auth required pam_frprint.so account required pam_frprint.so password required pam_frprint.so session required pam_frprint.so
Example 30.6. Proxy Identity and Authentication
proxy_pam_targetfor the authentication PAM module and
proxy_lib_namefor the service, like NIS or LDAP.
[domain/PROXY_PROXY] auth_provider = proxy id_provider = proxy proxy_lib_name = ldap proxy_pam_target = sssdproxyldap enumerate = true cache_credentials = true
- Create an
/etc/pam.d/sssdproxyldapfile which requires the
auth required pam_ldap.so account required pam_ldap.so password required pam_ldap.so session required pam_ldap.so
- Make sure the
nss-pam-ldappackage is installed.
[root@server ~]# yum install nss-pam-ldap
- Edit the
/etc/nslcd.conffile, the configuration file for the LDAP name service daemon, to contain the information for the LDAP directory:
uid nslcd gid ldap uri ldaps://ldap.example.com:636 base dc=example,dc=com ssl on tls_cacertdir /etc/openldap/cacerts