20.4. Caching Kerberos Passwords
A machine may not always be on the same network as the IdM domain; for example, a machine may need to be logged into a VPN before it can access the IdM domain. If a user logs into a system when it is offline and then later attempts to connect to IdM services, then the user is blocked because there is no IdM Kerberos ticket for that user. IdM works around that limitation by using SSSD to store the Kerberos passwords in the SSSD cache.
This is configured by default by the
ipa-client-installscript. A configuration parameter is added to the
/etc/sssd/sssd.conffile which specifically instructs SSSD to store those Kerberos passwords for the IdM domain:
[domain/example.com] cache_credentials = True ipa_domain = example.com id_provider = ipa auth_provider = ipa access_provider = ipa chpass_provider = ipa ipa_server = _srv_, server.example.com krb5_store_password_if_offline = true
This default behavior can be disabled during the client installation by using the
This behavior can also be disabled by editing the
/etc/sssd/sssd.conffile and removing the
krb5_store_password_if_offlineline or changing its value to false.
[domain/example.com] ... krb5_store_password_if_offline = false
The SSSD configuration options for Kerberos authentication is covered in the "Configuring Domains" section of the SSSD chapter in the Red Hat Enterprise Linux Deployment Guide.