Two Factor Authentication is a lofty goal for any linux administrator. If you’re lucky enough to have access to an NetIQ eDirectory server, hardware based two factor authentication is closer than you think.
Tutorial on how to use SSSD (pronounced Triple “S” D) as a cross Linux platform (RHEL, SLES, Ubuntu, et. al) authentication agent instead of painful and often times disparate pam_ldap and sudoers configurations. Centralized user and group management using existing directory infrastructure. Learn how centrally store SSH key and sudoer configurations in LDAP. No more having to copy your SSH key to each new server. Create a SSH Key based single sign on solution. Your sudo commands are authenticated against your Directory. Expand the configuration of SSSD clients for 2 factor authentication using a HOTP configured YubiKey that does not require any changes on the authenticating client. Integration with eDirectory. Explore SSO Kerberized options with Active Directory and MIT Kerberos.
